The Lock-It-Down Handover: Changing Accountants Mid-Year Without the Scramble

Changing accountants mid-year can feel like swapping pilots halfway across the Channel. In reality, it is a normal bit of business admin. Sole traders do it. Landlords do it. Limited companies do it. The trick is to make the handover boring, documented and deadline-proof. That is where the Knox Box comes in.

The Knox Box is our plain-English handover framework. Think of it as five boxes you pack, check and lock before you close the door on the old arrangement. Lock it down safely, and switching accountants becomes a change of adviser rather than a change of momentum.

Box 1: Dates — lock the calendar first

Before you move a single receipt, write down every date that matters. That means VAT returns, payroll, MTD quarterly updates, Self Assessment, company accounts, confirmation statements, and any payment on account. If a deadline is close, decide now who is filing it: the old accountant, the new one, or you.

A mid-year switch is much calmer when both sides know the cut-off date. Agree the date from which the new accountant takes over. Put it in writing. Then diarise the next three deadlines so nothing slips while everyone is being polite about the handover.

Box 2: Records — box up the paper trail

Gather the records your new accountant will need. For most small businesses, that includes bookkeeping records, bank statements, sales invoices, purchase receipts, payroll records, VAT returns, previous accounts and tax returns, and any correspondence with HMRC. If you use accounting software, make sure the new accountant can access the file or receive an export.

Do not forget the less obvious items: fixed asset lists, loan agreements, mileage logs, use of home claims, lease documents, and details of any payment plans with HMRC. If you are a landlord, keep property income and expenses clearly separated. If you are a limited company, include company accounts, confirmation statements and details of directors loans or dividends.

Box 3: Access — sort permissions and software

Your new accountant will usually ask your old one for professional clearance and information. You will need to authorise that exchange. This is normal. It is not a secret handshake or a black mark against you.

Check who has access to what. That may include HMRC agent authorisation, VAT and PAYE online services, Companies House, accounting software, bank feeds and cloud storage. Use a secure portal or password manager rather than sending passwords in a casual email. Once the handover is complete, remove the old accountant from systems they no longer need. Lock it down safely means exactly that.

Box 4: Questions — ask the awkward ones now

Ask your old accountant what has been filed, what is outstanding, and whether there are any HMRC enquiries or payment arrangements in place. Ask about fees, work in progress and any records they are still holding. If there is a fee dispute, deal with it separately. Do not let it become a missed filing deadline.

Ask your new accountant what they need from you, what their fees cover, who will handle deadlines, and how they will communicate. Get the scope and fee agreement in writing. This is the best way to avoid paying twice for the same work. A clear cut-off date and a clear list of responsibilities are worth more than a vague promise to sort it out.

Box 5: Sign-off — keep the handover in writing

Finish with a simple handover note. It should list the records received, the filings completed, the open items, the next deadlines and who is responsible for each one. Both sides do not need a legal document for a straightforward switch, but a clear email trail is your friend.

If the old accountant is slow to hand over, keep asking politely and in writing. If a deadline is approaching, tell the new accountant immediately. Most problems in a mid-year switch are not caused by bad intentions. They are caused by silence.

Keep HMRC filings on track during the switch

Do not cancel direct debits for VAT, PAYE or payments on account just because you are changing accountant. Payments and representation are separate things. Keep paying what is due unless you have agreed a change with HMRC.

If a filing deadline falls during the handover, decide who is doing it before the week it is due. It is fine for the old accountant to file the final return for their period, and for the new accountant to take over afterwards. What is not fine is assuming someone else has it covered.

A sensible timeline

For a straightforward sole trader, two to four weeks is a comfortable handover window. Allow longer if there is VAT, payroll, a limited company, overdue bookkeeping or an HMRC enquiry. Start now rather than in the week before a deadline. Mid-year switches are common, and a good accountant will have a process for them.

The takeaway

You are allowed to change accountants. You are allowed to want clearer communication, a different fee structure or a better fit. The Knox Box is simply a way to do it without losing receipts, missing deadlines or paying for the same work twice. Pack the five boxes, lock them down safely, and keep the business moving.