Lock-up comes down when work is billed sooner and fees are collected on an arrangement agreed at engagement. In practice that means billing on a fixed routine, collecting recurring fees by direct debit, and handling the few clients who cause most of the delay differently from everyone else. Measure the two halves separately each month so you can see which change is working.
In this article
The short version
- Split lock-up into WIP and debtors and start with the bigger half.
- Bill on a fixed routine, move recurring work to monthly fees and bill extras as they happen.
- Agree payment at engagement, ideally with a direct debit mandate signed alongside the proposal.
- Give the few persistent late payers different handling, and automate the routine reminders.
- Measure both halves monthly from the same report.
Find out which half is holding cash
Lock-up is your unbilled work in progress (WIP) plus the fees you've billed and not yet been paid. The two halves have different causes, and usually different owners in your practice. Your WIP grows when nobody decides to bill. Your debtors grow when there's no agreed way for the fee to reach you.
So before changing anything, split your figure. Work out WIP days and debtor days separately, using your annual fee income: £20,000 of WIP on £400,000 of fees is about 18 days, and £60,000 of debtors is about 55 days. Take the reading on the same day each month, from the same report, and write down your definition so it doesn't drift.
Start with whichever half is bigger. In many small practices it's the debtors half, though yours may differ.
Bill sooner and on a routine
Work tends to sit unbilled because billing competes with client work for the same hour of your week, and an unraised fee note is invisible to everyone. A routine takes the decision away from you.
- Give every client a billing date they already know about, whether that's monthly, on completion of each job or at set stages.
- Move recurring compliance work to a fixed monthly fee. You bill it on the same date every month, so it never builds up as WIP.
- Bill longer jobs in stages rather than waiting for the end.
- Bill out-of-scope work as it happens. The longer extra work waits, the harder the fee note tends to be to send.
- Check the due date on each fee note. A due date that's already passed when the client receives it leaves them nothing to aim for.
In most practices, whoever ran the job owns the billing decision. If you review WIP older than 30 days once a month, listed by job and by person, you'll usually keep it moving.
Agree how fees are paid at engagement
The easiest time to agree how you'll be paid is when your client is agreeing everything else. Once a fee note is overdue, you'll find the same conversation much harder.
A fee note with no agreed way of paying depends on the client remembering, finding your bank details and typing a reference. One collected under a mandate the client signed at engagement doesn't: it's taken on the date you set, and if a collection fails, you know straight away and can follow up.
For recurring fees, direct debit gives you a collection date you choose, and you can change the amount from month to month under the same mandate as long as your client gets advance notice. If a client won't use direct debit, you can still send a payment link they can pay by card or pay by bank.
If you send proposals through Socket, Engager.app or Sodium, Adfin can put the direct debit mandate into the same step, so your client signs it while accepting the engagement. Collections then run without anyone raising them, and every payment is reconciled against the right fee note in Xero or QuickBooks.
Treat persistent late payers differently
Sort your aged debtor report by client, then look back over the last year at who paid late more than once. You'll probably find a short list of names, and often the same names from one quarter to the next.
Those clients need different handling from you: a mandate, payment before work starts, shorter stages, or a conversation about whether the work continues. Most of your other clients just need a clear fee note and a reminder or two.
The reminders are the part that tends to slip in your busiest months. Adfin's AI Customer Agents can take that on, chasing each client by email, SMS or WhatsApp at the intervals and in the tone you choose, and sending a statement when a client goes quiet. The rules are yours, and anything that needs a partner's judgement comes back to the partner who knows the client.
Common questions
What's the quickest way to reduce lock-up? Split it into WIP and debtors first, then work on the larger half. For many small practices that's debtors, where agreeing direct debit at engagement often helps.
Should I bill longer jobs in stages? Usually, yes. Billing at set stages stops a long job building up as WIP until the end, and your client gets smaller, more frequent fee notes instead of one large one.
What should I do about clients who are always late? Look at who paid late more than once in the last year and handle them differently: a mandate, payment before work starts, shorter billing stages, or a conversation about whether the work continues.
Do clients have to agree to direct debit? Yes. Each client signs a mandate, and they can cancel it at any time. Asking at engagement, alongside the engagement letter, is usually the simplest moment.
Will clients object to paying by direct debit? Some will. Many accept it when it's presented at engagement as the standard way to pay a monthly fee, and you can offer card or pay by bank to those who don't.
Who in a practice should own lock-up? Usually whoever runs each job owns its billing, and one named person owns collection. A monthly review of both halves keeps them from being traded off against each other.
Sources
- Direct Debit - The Direct Debit Guarantee (accurate as of October 2026) https://www.directdebit.co.uk/direct-debit-guarantee/
- GOV.UK - Late commercial payments: charging interest and debt recovery (accurate as of October 2026) https://www.gov.uk/late-commercial-payments-interest-debt-recovery/charging-interest-commercial-debt
- Adfin - Direct debit payments (accurate as of October 2026) https://www.adfin.com/direct-debit-payments
- Adfin - Credit control (accurate as of October 2026) https://www.adfin.com/credit-control
