The things every rep needs to know about mileage claims:
Outside of office hours you can claim up to 45p for mileage. Mileage payments up to 40p are tax free. Everything over 40p is taxable as income.
Inside office hours Mileage is the distance from the instructing solicitors office to the venue or the actual mileage, whichever is the shortest. The expectation is that you will use public transport. You can still use you own car but payments are capped at 25p per mile. To claim 45p per mile you will need to show a justification. The Criminal Bills Assessment Manual gives the following reasons:
The LAA are trying to crack down on inflated or spurious travel claims. They are being a bit nutty and are querying even very small claims. Invoices & receipts should always be produced in support of claims for travel expenses. Under the contract, claims for for travel of up to £20 do not require receipts but even those are being queried so it is best to keep all reciepts with your notes.
Do check the Criminal Bills Assessment Manual which you will find a terrific and thrilling read. Take a look at s3.9 Travel and Waiting.