If it's getting work done that is required for the MOT or the MOT itself, and it is a pre-booked
appointment, then aso long as you are insured to do so, I believe you are allowed to drive it there. Obviously providing it doesnt have any major defect that would seriously comprimise the road-worthyness of it.
Im not 100% sure on this however, it's just the way I have alway's understood how the MOT law's to work; you can't tax a vehichle unless it has an MOT, so the tax issue should
be irrelevant I think.
Im sure someone else can advise better.