Actors

I've been asked to complete a tax return for a young actor. I'm used to working as a management accountant but feel I should be able to do this but I can't seem to find anything much as to what he can claim against his acting income. I get the 'wholly for use in the business' etc but what about travel expenses. If he has to go travel miles for rehearsals can he claim any mileage? Does anyone know of anywhere I can get the information needed to make sure  he's getting the relief he's entitled to.

Thanks