https://www.slab.org.uk/faqs/transfer-of-solicitor/
In terms of paragraph 18 of the Notes on the operation of Schedule 1A, where agency is transferred from one solicitor to another:
No fee can therefore be paid to the transferring solicitor for a block of work not completed at the point of transfer unless and until the remaining work of that block is completed.
Similarly, no fee is payable to the transferee solicitor in respect of the perusal of any documentation that has already been made available and perused by the transferring solicitor where:
Mindful that the perusal charges in a case cannot be determined until the case concludes no perusal charges can be allowed in a case until we can establish what preparation fee is payable in the case.
Where there is a transfer of solicitor our approach will be to apportion equally the perusal volume which is included in the preparation fee. For example, in any case where there had been a transfer and two solicitors are entitled to payment we will expect each solicitor to deduct:-
Given that certain block fees are payable for “all work” (and can only be paid once in any case) related to the case we will be unable to determine what proportion, if any, of the fee is payable prior to the conclusion of that block of work.
In order to calculate what fee is payable we must be able to determine:
Where a block fee has been claimed and disallowed as a result of a transfer the assessment officer responsible for assessing the final (solicitor who has concluded the case) account will establish what payments are due to all solicitors in the case and make payment of the appropriate sum that is due.