No knowledge and Sarah, your answers are a little silly, if I may say so. You are assuming that this person has a dangerous and unroadworthy car.
Please bear in mind that an MOT covers the state of the cars roadworthiness at time of testing. That testing is down to the personal opinion of one MOT tester, who may or not be sensible when it comes to testing. There are testers who do everythng to the book, there are testers who do more than the book, there are testers who will use a little discretion. And of course there are testers who will advice that the lower sprocket gasket flange is dangerous, but we can fix it here for you in an hour for fifty quid mate.
If you had a number plate light out, would you prefer a fail, or a "get a new bulb in a drop the car back and show us?"
As far as I am aware, you can take a car for an MOT anywhere, but the new system will flag up that the car has been taken to two separate testers, and may cause questions to be asked.