I thought that when you take your car in, most MOT places will ask if you want to put a cap on work (if any) that needs doing to pass, i.e. you could say £50 so if you need a new bulb or windscreen wiper they can do the work there & then to pass your car? If the work needed is more than your cap, they call you to ask if you want them to do it, or if you want someone else to do it and come back for a re-test.
Been a long time since I had an MOT (about 10 years! lol), but that's what they did for me.
how the individual garage does it is up to them i suppose but I always tell them if its less than £50 fix it! saves alot of hastle!