I've always been suspicious that some garages don't do all the work they charge you for.
One tip I've heard is to put a small scratch on your oil filter. Then if they just wipe it clean rather than change it, you'll know.
I guess you could put a small blob of Tippex on a wheel nut where it touches the wheel, to see if a wheel has been removed, but perhaps brake pads can be checked without taking the wheels off.
Does anyone know of any other checks I can do ?
Many Thanks Steve.