Revenue recovery for professional firms: audit, collection or process fix?

Author: Adam Khalid, Founder and CEO, Intel Made Simple. Sources last checked 28 October 2026.

A partner who decides the firm is leaking cash faces an early choice of route. Hire a collector to chase old debts. Commission an outside review of the whole cycle. Or fix the firm's own process and keep the work in house. The right answer depends on where the cash is stuck, and most firms choose before they have measured. This guide sets out what each route can and cannot reach, what the law lets a firm do itself, and a checklist for choosing.

We sell one of these routes, so read this with that in mind. Where a claim rests on a source, the source is linked. Where it is our judgement, we say so. This is general information, not legal advice.

What is revenue recovery for a professional firm?

Revenue recovery means getting back money the firm has earned and not collected. It splits into two jobs that need different tools. The first is recovering what is already invoiced and overdue. The second is recovering what is earned and not yet invoiced, plus what is lost at the point of pricing. The ILFM defines lock-up (opens in a new tab) as the time it takes a firm to convert work undertaken into cash received, built from WIP days before the bill and debtor days after it. A collector can only act on the second half of that definition.

What did we find when we searched for it?

On 28 October 2026 we searched Bing UK for “revenue recovery consultancy UK professional firms”. The results were generic profit-recovery, debt-collection and directory pages. None served professional firms specifically. That is a statement about that one query on that day, not a claim about every provider. It does mean a partner who types the phrase will find services built for retail and supplier-invoice recovery before they find anything designed around WIP, recovery rate and engagement letters.

Which half of the cycle is larger in your firm?

Measure before choosing. Our working formulas, built on the ILFM definition: WIP days equals unbilled WIP divided by daily fee income, and debtor days equals unpaid billed fees divided by the same figure. Our arithmetic on invented figures: with £2,000,000 of fees and daily fee income of £5,479, WIP of £250,000 is 45.6 days and debtors of £330,000 are 60.2 days. Here the debtor half is larger. A collection route would reach only that half, and the earlier half would keep leaking.

Now reverse the split: WIP of £420,000 is 76.7 days and debtors of £150,000 are 27.4 days. A collector has little to do in that firm, because the money is not stuck in invoices. It is stuck in unbilled work. See our guide to unbilled WIP.

When is a collection route the right move?

Use collection when the invoices are valid, the term has passed, the client has stopped replying and you have run your own ladder. Before you hand a debt over, know what you can do yourself. GOV.UK states that statutory interest on late business payments is 8% plus the Bank of England base rate (opens in a new tab), and section 5A of the 1998 Act (opens in a new tab) gives a fixed sum of £40, £70 or £100 by debt size. The general Practice Direction on Pre-Action Conduct sets the steps before a claim, as our late payment guide explains.

If the debtor is an individual or a sole trader, the Pre-Action Protocol for Debt Claims (opens in a new tab) applies instead, with a 30-day reply period from the date on the Letter of Claim. Whoever sends that letter, whether your firm or an agent, needs to follow it. A debt also runs towards a time limit: for a simple contract, section 5 of the Limitation Act 1980 (opens in a new tab) sets six years from when the cause of action accrued. An old ledger is a reason to act, and a reason to take legal advice first.

If a debt becomes bad, HMRC's VAT guide (Notice 700) (opens in a new tab) says you may be able to reclaim relief from VAT on it. Ask your tax adviser.

When is an outside review the right move?

Use a review when you cannot say which half of the cycle is larger, when the figures sit in three systems, or when the partners disagree about the cause. The output should be a measured split between WIP and debtors, a recovery rate by work type, and a ranked list of leak points with a pound value on each. If a review ends in a report with no owners and no dates, it has not recovered anything. We say the same about our own work: every aged matter leaves with a name and a date against it.

Ask any reviewer, including us, for four things in writing before you commission the work: the data they need and how it will be handled, the deliverable in plain terms, a fixed price, and how long they will keep your data afterwards. Where client records are involved, read our guide to UK GDPR and AI client data first. A reviewer who is unwilling to put those four things on paper is not ready to touch your ledger.

When is a process fix the right move?

Fix the process when the same leak recurs. ICAEW's guidance on fees and charge-out rates (opens in a new tab) is a good model of what a fix looks like in practice: quantify extra work when the fee is agreed, review jobs with poor recovery for causes that apply to every future job, shorten the time from start to completion, give staff time budgets, and avoid rounding fees down. The ILFM adds billing at appropriate milestones, regular matter review, and shared expectations between fee earners, partners, management and finance.

A process fix is slower than a collector and cheaper in the long run, because it removes the cause. Its risk is drift: without a monthly measure the habits return. Keep the WIP-days and debtor-days line on one page every month.

How do you choose? Seven questions

1. Do you know your WIP days and debtor days for the last twelve months on one basis? If not, measure first.
2. Which half is larger? If WIP, a collector cannot help. If debtors, collection and chasing come first.
3. What is your recovery rate on your ten biggest engagements? If it is below where you want it, the cause sits at pricing and scope.
4. How old is the oldest debt that matters? Check the limitation date, take legal advice, and act first on the oldest.
5. Who are the debtors: companies, sole traders or individuals? The pre-action steps differ.
6. Who owns each aged matter or debt, and by what date? If nobody, assign that before spending anything.
7. Will anything you buy leave your people with a routine, or only with a report?

What does our route cost?

We publish prices on the pricing page. The first step is a free Leak Scan that shows where cash leaves the chain. After it, a stage build or an AI Readiness Audit is £1,500 and all five stages are £6,000. We add a success fee of 15 to 25% of the money recovered above your baseline, for 12 months, and we do not chase your clients on your behalf. Our pillar guide on revenue leakage shows how the five leak points connect.

What is the difference between debt collection and revenue recovery?

Debt collection acts on invoices already issued and overdue. Revenue recovery in our usage also covers work not yet billed and money lost at pricing and scope, which a collector cannot reach.

Can a professional firm charge interest on late invoices itself?

Yes. GOV.UK states that statutory interest on late business payments is 8% plus the Bank of England base rate unless a contract sets a different rate. Send a new invoice if you decide to add interest.

Do the pre-action rules change if the debtor is a sole trader?

Yes. The Pre-Action Protocol for Debt Claims applies to a business claiming payment of a debt from an individual, including a sole trader, and does not apply to other business-to-business debts. The Letter of Claim starts a 30-day reply period.

How long do you have to claim an unpaid invoice?

For a simple contract, section 5 of the Limitation Act 1980 sets six years from the date the cause of action accrued. Take legal advice on the date for your own contract.

Should a firm measure its leak before buying help?

Yes. WIP days, debtor days and recovery rate on the last twelve months show which route fits. A firm with large unbilled WIP and small debtors gains little from collection.