How we take Solo to UK construction subcontractors from launch through to the end of March, what it costs at three budget levels, and what we will know at each step.
Start here ↓The plan is the spine: thirteen questions, each answered in a page or less, about twenty minutes end to end. Five deep-dives sit behind it for whoever will run that part. Everything ends in the same place: the decisions we need from you.
Sections 01 to 13, in order. Each one answers a single question and hands you to the next: what we're selling, to whom, with what message, where, what happens after the download, when, for how much, and how we'll know.
Start at 01 →Five deep-dives, one for each piece of work behind the plan. You don't need all five: read the ones for the work you'll run or sign off.
See the deep-dives ↓Section 12 lists nine decisions and six product asks. Section 14 records your answer, whether that's a tick or a list of changes.
Go to the decisions →Each is long and built as a reference. Read its opening section, then come back to the rest when that work starts. They run in the same order as the plan, and each one points you to the next.
Solo launches in October on iOS and Android. It handles the money side of a subbie's trade: invoicing contractors with the CIS deduction shown before sending, tracking what's been taken, logging expenses, and preparing quarterly reports.
A one-month trial on every account, then it falls back to Free with no card. Standard is £25 a month and Plus £45, both plus VAT. So the advert sells a free install, and the decision to pay happens later, inside the app.
A subbie invited by a contractor already has a reason to finish a long sign-up. A subbie who arrives cold from an advert does not. This plan buys the second group with advertising, reaches the first through their contractors (section 05), and never measures the two as one.
About 880,000 registered CIS subcontractors. Nobody is speaking to them in paid social about CIS: roughly five live UK adverts mention CIS subcontractors, against about 220 on Making Tax Digital.
The launch date within October. The brand name for ad accounts, handles and store listings. The targets for installs, sign-ups and paying users. That the budget is media only. And a read of the Claims Register, which we have not seen yet — every message here is a candidate for testing, not approved copy.
Drawn from 150 things real subbies, their partners and their accountants have written in public, alongside your brief. Their words matter: they say a payslip, not a deduction statement; tax gets stopped; the money back in April is a rebate.
| Who | How they get paid | What they say | What we lead with |
|---|---|---|---|
| The invoicing subbie | Sends invoices, labour and materials | "Can't put a minus figure in the invoice for cis." Wants to invoice before leaving site. | See what you'll be paid before you send it |
| The weekly payslip subbie | Hands in hours, paid weekly with a contractor's payslip, sometimes a text | "didn't have all payslips so had to give just gross total" | Every payslip in one place |
| Stuck on 30% | New starters waiting on a UTR, recent arrivals, records that don't match | "Just invoice and take the 30 percent hit" | Know your rate: 20%, 30% or gross |
| Whoever does the books | Usually the partner, at the kitchen table | "googling for about three days solid and I am still clueless" | Set it up once, in ten minutes |
| Gross status | No deductions, sets tax aside | Raids the tax pot when work is quiet | Not a launch segment |
Each of these is a hypothesis with evidence behind it. Each goes through the Claims Register before it is made. None of them promises a tax outcome, a refund, or anything HMRC has approved.
| The angle | Why we think it works | Who it's for |
|---|---|---|
| See what you'll be paid before you send it | It is what the product does, and no live UK advert says it. A search for "CIS invoice" in the ad library returns nothing at all. | Invoicing subbie |
| Every payslip in one place | Statements go missing, arrive as texts, or never come. HMRC won't readily show a subbie their own record. | Weekly payslip subbie |
| Free. No card. | Free tools already set the price expectation at zero in this category. The free tier is the honest way in. | Everyone |
| Built for subbies, not office workers | Straight from their reviews of other apps. Competitors talk to "freelancers" and "sole traders". | Invoicing and payslip subbies |
| Whoever does the books can set it up | Partners do the setup and ask the questions. | Whoever does the books |
Refund or rebate amounts. "HMRC-approved" or "HMRC-recognised". Anything about filing or paying tax on someone's behalf. Employment status guarantees. Anything implying Solo holds money. Competitors by name. Prices without "+VAT". Several competitors use these lines freely; we are not going to match them.
Voice and messaging: how Solo sounds, the words subbies use, and every candidate line with its Claims Register status.
| Channel | Its job | What we know |
|---|---|---|
| Meta (Facebook, Instagram) | The engine. Reach and installs at volume, then better users as it learns | Where this audience is, and where the CIS conversation isn't happening |
| TikTok | Site humour and trade voices; cheap reach | UK rules put accounting and tax ads under restrictions. We clear that before we build for it |
| Apple Ads (App Store search) | Catch people searching the store for CIS help | Store results for "cis tax" are held by apps with fewer than ten ratings |
| Google Search | Catch the small, cheap, high-intent demand | About 4,200 searches a month we can honestly answer, at 30p to £1.85 a click |
| Creators | Proof from people they already trust | It is how this category buys installs. On the Tools and the shortlist give us a running start |
| The app store listing | Turns every visit into an install | Free to improve, and it lifts every other channel |
| Outreach (email, text, calls, post) | Reach trade businesses and bookkeepers by name | The rules differ for limited companies and sole traders. Valla's solicitor reads them before any send |
| Contractors (hubs) | One yes brings about ten solos | Section 05 |
The website: our home base, the topical map, the glossary, and how Google and AI answers find us.
Video and social: the bodge-and-voiceover format, the series, the account rules and the cost.
PR and amplification: the stories, trade press, creators, events and calendar.
Outreach: email, SMS, calls and post, segment by segment.
We are not joining the Making Tax Digital fight at launch. About 220 live UK adverts already shout about it, from Xero, Sage, Tide and everyone else. We can enter that conversation in January, when the deadline pressure is real and our claims are settled — and even then, in their language rather than the industry's.
Next · 05How do we reach solos through their contractors? →A hub is a contractor who pays several subbies. When a hub joins, it invites its subbies, and they arrive with a reason to finish setting up. So hubs are not a second market. They are the cheapest route to solos we have. The paid plan stays the base, because it works without any contractor saying yes; this route sits on top of it.
HMRC counts about 880,000 registered subcontractors and 143,400 active contractor schemes, and a subbie works for more than one contractor in a year. That puts a typical small contractor at 6 to 15 subbies; about 10 is our working figure. Your own client book would give the real number.
The contractor account costs nothing, and every invoice a solo sends already carries an invitation to open one. The product does half the selling. The job here is to make sure the other half happens.
1,070 active construction companies whose filed accounts mention CIS, drawn from Companies House and already built. Behind them sit 203,947 active trade limited companies.
| Route | How it works | Who it reaches |
|---|---|---|
| The invoice itself | Every invoice a solo sends lands with a contractor. Tag the links in that email. If someone opens it and doesn't join, follow up with a short sequence and a link to book a call | Whoever pays the subbies, often the person doing the books rather than the director |
| Sam, Luke and Lena post as themselves, and message directors and commercial managers at the 1,070 firms by name, a few each day | Directors and commercial managers | |
| Email and calls to limited companies | The outreach pipeline, pointed at contractors. Valla's solicitor confirms the rules before any send | Limited-company contractors |
| Bookkeepers and accountants | One bookkeeper can run CIS for many contractors. 164 CIS bookkeepers and accountants are on file, with a partner offer to test | Several contractors at once |
| Solos asking their contractor | After a solo's first invoice: "ask your contractor to join, free", with a message ready to forward | The contractor, from someone they already pay |
People, not budget. Our July working put one caller at about three or four small contractors a month. So the first six months prove two numbers, solos per contractor and how many invited solos finish setting up, and the month-3 review decides whether to hire against them. Until then the founders' LinkedIn, the invoice email and the bookkeepers carry it.
Outreach: the Companies House list, the bookkeeper offer, and the route for each group.
Advertising buys the install. Whether that turns into a paying user is decided inside the app and in the messages that follow it. This is the plan for that part, and it needs the product team as much as it needs us.
| Stage | What we do | How we'll know |
|---|---|---|
| First 48 hours get to the first invoice | In the app: ask for the UTR and National Insurance number when they're needed, not on the second screen, and show what's missing before the first send. Messages: a welcome on day 0; "why we ask for your UTR, and where to find it" on day 1, by text on day 2; a "spot the mistake" invoice on day 3 | First invoice sent within 48 hours. Apple's measurement reports its first results from the first two days, so this window matters twice |
| First month make it a habit | First invoice sent: "Nice one", plus the referral ask. Days 7 and 14: every statement in one place. Each month around the 19th, when statements should be in: a text, for those who opted in. Notifications when an invoice is due or paid | Active in week 2 and week 4 |
| Free to paid | Before the trial ends, say plainly what changes. Make the upgrade screen say what you get in subbie words. Test the upgrade moment with the product team in month 5 | Trial to paid, split by invited and advertised |
| Referral | A solo-to-solo link after the first invoice, and the contractor invite from section 05. The reward is your call; ours to test is a free month for both | Invites sent per active user, and installs from them |
| Retargeting | Three groups: installed but didn't sign up; signed up but no invoice; visited the website but didn't install. Paid from the existing channel lines, not new money | Cost to win one back, against the cost of a new one |
| Ratings and the store listing | Ask for a rating after a success, such as the first invoice sent, never on first open. Screenshots that show an invoice with the CIS line already worked out | Number of ratings and store conversion |
| Help and replies | A way to get help inside the app (there isn't one yet). Advert comments answered within a working day, without giving tax advice. Questions that keep coming back go to the product team | Reply time, and the top five questions each month |
| Win-back | Quiet for 30 days: one message tied to a real date, such as statements, 31 January or Making Tax Digital from April 2027 | Users who come back |
Collect a phone number and a marketing opt-out at sign-up, or no text message can be sent. And pass the in-app events to the measurement tools, or none of these messages can be triggered. Email and text run on Loops (about £37 a month) or Customer.io (about £75, which adds texts and notifications).
Lifecycle email and text: the full sequence, and draft messages in the voice guide's words.
Six months from launch, plus the weeks before it. The shape follows how this market behaves: December goes quiet, and January to March is when tax lands in everyone's mind.
| Month | What it's for | What we'll have at the end of it |
|---|---|---|
| Month 0 before launch | Accounts, tracking, the landing page, the creative bank, creator deals, store listings. Welcome emails built, sending domains warmed, the contractor list enriched | Everything in place to spend on day one, and tracking proven with a small live test |
| Month 1 October | Go broad. Four or five angles across Meta, TikTok, Apple Ads and Search, so the platforms and we learn fast. The contractor route opens: founders on LinkedIn, invoice links tagged | Real cost per install by channel, and the first read on which messages get people through sign-up |
| Month 2 November | Narrow. Split the winners by segment, add Google app campaigns, test the landing page against sending people straight to the store | Cost per onboarded user by channel and by angle. Where people fall out of onboarding. The first read on solos per contractor |
| Month 3 December | The quiet month. Spend light, build January's creative, improve the store listings and the content | The first read on how many free users start paying, from the October cohort |
| Month 4 January | The surge. Tax is on every subbie's mind before the 31st, and Making Tax Digital searches peak | Our best month for volume, and the first honest cost per paying user |
| Month 5 February | Scale what pays. Push referrals and reviews. Work with the product team on the moment people decide to pay | A repeatable acquisition engine with known numbers |
| Month 6 March | Set up April: the end of the tax year is when this audience pays attention. Write the next six months on real data | A plan for April onwards built on evidence, not benchmarks |
By the end of December we will have a full cohort through the trial, so the second half of this plan can be rewritten on what actually happened rather than what we assumed in September.
Media only. The monthly average holds at the level you choose, but the months are not equal: December is quiet and January to March is when this audience is paying attention.
| Level | Oct | Nov | Dec | Jan | Feb | Mar | Six months |
|---|---|---|---|---|---|---|---|
| Small | £10k | £10k | £6k | £12k | £12k | £10k | £60k |
| Medium | £15k | £15k | £9k | £18k | £18k | £15k | £90k |
| Large | £20k | £20k | £12k | £24k | £24k | £20k | £120k |
| Channel | Small | Medium | Large |
|---|---|---|---|
| Meta | £4,000 | £5,500 | £7,000 |
| TikTok | £1,500 | £2,000 | £3,000 |
| Apple Ads | £1,000 | £1,500 | £2,000 |
| Google Search | £700 | £1,000 | £1,000 |
| Google app campaigns | — | £2,500 | £4,000 |
| Creators | £1,800 | £2,000 | £2,500 |
| Held back for the winner | £1,000 | £500 | £500 |
| Total | £10,000 | £15,000 | £20,000 |
Google's app campaigns need a certain daily size before they can learn. At the small level that money works harder elsewhere in month one, so they start in month two.
Published figures for this kind of app put an install somewhere between £3 and £10. That is a wide range because no one publishes numbers for a UK CIS app, so month one exists to replace it with ours. On those figures the first month buys roughly:
| Level | Installs in month 1 | What we learn |
|---|---|---|
| Small | 1,000 – 3,300 | Enough to read cost per install and sign-up rate by channel |
| Medium | 1,500 – 5,000 | The above, plus enough volume for the platforms to optimise properly |
| Large | 2,000 – 6,700 | The above, plus a faster read on segments and creative |
Across free apps of this kind, about two in a hundred people who download go on to pay within the first month or so. If that holds here, and an install costs £6, then each paying customer costs around £300 in advertising — a year of Standard before it washes its face. That is not a reason to spend less. It is the reason months one to three are judged on installs, sign-ups and first invoices sent, and why the biggest wins available to us are inside the app: getting cold users through sign-up, and the moment the free tier asks them to upgrade. We would rather say this in September than explain it in December.
| Item | Cost | Where it's worked out |
|---|---|---|
| Outreach: letters, email, calls | about £2,000 in month 1 | Outreach deep-dive |
| Email and text after sign-up | £37–£75 a month | Section 06 |
| Video production | £280–£2,600 a month | Video deep-dive; the voice decides where in the range |
| Measurement (Singular, Firebase, PostHog) | free at launch volumes | Section 09 |
| The contractor route | people's time | Section 05 |
If the £10k, £15k or £20k a month is for media only, these sit on top of it.
If the round closes in month two or three, we do not simply spend more. We scale only the channels and messages that have already proved a cost per onboarded user we are happy with, and we add the things that take longer to pay back: content, store visibility and a wider creator programme. The month-three review is the natural moment to reset the numbers.
Next · 09How will we know it's working? →| Number | What it means | First honest read |
|---|---|---|
| Cost per install | What we pay for a download, by channel | Week 1 |
| Sign-up rate | How many opened it and made an account | Week 2 |
| Cost per onboarded user | Through sign-up and set up, ready to use it | Weeks 2–3 |
| Activation | First invoice sent within a fortnight of installing | Weeks 3–4 |
| Cost per paying user | What it costs to win a Standard or Plus subscriber | Weeks 6–9 |
| Solos per contractor | How many subbies each contractor who joins brings in | Month 2 |
Invited subbies and advert-driven subbies are counted separately throughout. If they are blended, the invited users' higher completion will make the advertising look better than it is, and we will scale the wrong thing.
Reporting is a short written summary each week — what we spent, what it bought, what we changed, what we are doing next — plus a monthly review of the numbers with Lena.
Next · 10What are we testing? →| Month | The question | How we decide |
|---|---|---|
| 1 | Which channel and which angle brings subbies who finish setting up? | After a fortnight and £1,000 on a channel, anything costing more than twice the best one drops to a minimum |
| 2 | Does speaking to one segment beat speaking to all of them? | Segment-specific adverts against the broad winner, judged on cost per onboarded user |
| 3 | Does a landing page beat sending people straight to the store? | Split the traffic; the deduction calculator page is the test's centrepiece |
| 4 | How far can the winning combination scale before it gets expensive? | Raise budgets in steps while watching cost per onboarded user, not daily noise |
| 5 | What turns a free user into a paying one? | Work with the product team on the upgrade moment; test messages to free users |
| 6 | What should the next six months look like? | Rebuild the plan on our own numbers rather than published benchmarks |
Every test gets a written question, a number that decides it, a budget and a date. Nothing runs on because it feels promising.
Next · 11What could go wrong? →| Risk | What we do about it |
|---|---|
| The measurement code misses the launch build | Decide the tool this week so the developers can include it. If it slips, we spend only where we can still measure, and hold the rest back |
| TikTok's UK rules restrict tax and accounting adverts | Clear it as soon as the account exists, before any TikTok-specific creative is made. If it doesn't clear, that budget goes to Meta and creators |
| Cold users stop at the tax number and UTR screens | We will see exactly where they stop in week two and hand the product team the numbers. Showing value before asking for data is the fix, and it sits in the app, not in the advert |
| Price against cheaper, better-known software | Lead with free, and make Standard's case on what only Solo has: the contractor at the other end. Worth deciding together what Standard offers a subbie whose contractor isn't on Hub |
| The name is still open | Accounts, handles, store listings and the landing page all wait on it. Every week it stays open takes a week off the pre-launch runway |
Ten phone calls. You have subbies of your own. Fifteen minutes each with ten of them answers what no research can: do they invoice or get a payslip, what do they pay for help now, and who does their books.
Your wrong-invoice research. Real examples of invoices that were wrong, and why, is the best raw material for adverts that we have seen anywhere.
UK search demand and seasonality (Ahrefs, pulled 15 September). Competitor pricing, store listings and every live UK advert we could find across Meta, Google and TikTok (15 September). 150 public quotes from subbies, partners and accountants, each checked word for word against its source. Platform rules and ad policies, read on the platforms' own pages.
Every cost and conversion figure. There is no published data for a UK CIS app, so the ranges here come from published figures for finance and business apps, most of it reported by the companies selling the tools. Month one replaces all of it with our own numbers.
The Claims Register, the pricing document, Khristina's audience work, and the app itself — the test build has not let us in. Each of those could change details here, though not the shape.
Give it the tick and we'll start building to it. Want changes first? Note them below — every sign-off and change request is kept on record.
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