https://www.slab.org.uk/guidance/when-you-need-sanction-to-employ-an-expert/
You always need our prior approval to employ an expert witness.
In every application you must tell us what issues are to be addressed by the particular expert you are seeking.
While you need our prior approval to employ expert witnesses, you should check whether certain witnesses will be regarded as “experts” or not. To meet the description “witness”, the expert does not have to be called to give evidence.
Generally speaking, a witness may be deemed to be an expert where:
You do not need our prior approval for someone who is skilled or an expert in their field to be cited and give evidence that is factual. For example, you do not require our prior approval for a report from your client’s GP to report on what sort of medication they are receiving.
Any professional is only an expert witness if they are offering an expert opinion.
Procedures after legal aid is granted
Find out what documents/information should be provided when applying for approval for unusual expenditure or work likely to involve unusually large expenditure.
Procedures after legal aid is granted
Learn about what information Reporters will disclose in proof proceedings, when sanction is needed before taking precognitions and joint or shared precognitions