https://www.slab.org.uk/faqs/do-i-still-need-an-aa-increase-before-attending-a-police-station/
In the vast majority of cases, no. The old A&A increases are no longer needed for attending police stations.
For police interviews, the initial limit is now set at £550, so unless the attendance is very lengthy, or travel will exceed 2 hours, you don't need to get in touch with us before you set out.
For all other attendances at police stations, the initial limit is set at £225. You will only need prior authority for travel over two hours or for any other outlays which take the expenditure over £225.
In the event that an increase is required, this can be arranged in advance by telephoning: