Accounting Practice Workflow Software Cost in London (2026)

The verdict in three sentences

For a 30-person London practice, off-the-shelf practice management software costs £50 to £100 per user per month, or £18,000 to £36,000 a year before onboarding. A custom workflow platform built by a UK agency typically costs £30,000 to £70,000 (2026 ballpark), delivered in 4 to 6 months with Xero, QuickBooks, IRIS or Sage connectors. Custom pays off when your way of chasing client records and tracking Making Tax Digital deadlines is a competitive edge, and when it cuts client chasers by 25 to 35%.

What a practice workflow platform must handle

A 30-person firm typically runs 900 to 1,300 clients: sole traders, landlords, limited companies, a few charities. Since April 2026, sole traders and landlords with qualifying income above £50,000 must keep digital records and send quarterly updates under MTD for Income Tax, and the threshold drops to £30,000 in April 2027. That multiplies deadlines per client by four or five.

Your ledger tools (Xero, QuickBooks, IRIS) produce the numbers. They do not run production: who does what, by when, and which records are still missing.

Off-the-shelf or custom: the costed comparison

Tools such as Karbon, IRIS Practice Management or Xero Practice Manager are mature and quick to roll out. Their limits show when a practice organises production differently from the vendor model: sector teams, separate payroll units, two-level review.

The median scenario assumes £75 per user per month off the shelf (30 × 75 × 12 = £27,000 a year, £135,000 over 5 years) and a £52,000 custom build with £7,500 a year of maintenance. The curves cross around year three.

Kolonell prices its builds on a fixed grid in FCFA and EUR: a platform of this scope falls into our complex tier, 7,000,000 to 15,000,000+ FCFA (10,670 to 22,870+ EUR), with maintenance at 35,000, 75,000 or 120,000 FCFA a month (53, 114 or 183 EUR). Our team works from Dakar, on GMT, the same time zone as London in winter. Exact scope, connectors and hosting are set in the quote.

Typical 4 to 6 month plan

Practical tip: never cut over in January, when self assessment returns peak. Start in June, go live in October or November with a pilot team of 8.

Mini case study

Daniel, managing partner of a 30-person practice in London, handles 1,100 clients. Eighteen staff spend on average 3 hours a week chasing missing records, 54 hours a week in total.

With a client portal and automatic reminders, the firm targets 30% fewer manual chasers: 54 × 0.30 = 16.2 hours freed each week. Over 45 working weeks that is 729 hours. At a loaded cost of £40 an hour, the saving reaches £29,160 a year.

With a £52,000 custom build and £7,500 annual maintenance, payback arrives in just over 2 years on this line alone, before counting avoided licences or extra billable time.

FAQ

Do we need to replace Xero or IRIS?

No. The workflow platform connects to your ledger tool, and 90% of practices keep it. A connector typically costs £4,000 to £10,000 within a custom project (2026 ballpark).

Does it help with MTD for Income Tax?

Yes, mainly by generating the four quarterly updates and the final declaration per client and flagging missing records weeks ahead. Filing itself stays in your HMRC-recognised software.

Where is client data hosted?

UK or EU hosting is recommended under UK GDPR. Expect £120 to £500 a month depending on redundancy.

Can we start with one module?

Yes. Most firms start with the deadline engine and client portal, which deliver 60 to 70% of the gain, then add time tracking in phase 2.

How do we measure fewer chasers?

The platform logs every manual and automatic reminder. Compare 3 months before and after go-live, with a target of 25 to 35% fewer manual chasers.

Let's scope your project. We map your production process, pick the Xero, QuickBooks or IRIS connectors and plan delivery within 4 to 6 months. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.