as the owner of an mot station you could say im bias'd but i think not testing a car is madness, 50% of P6's i test have defective rear brakes, we have all seen utter rot boxes and collapsed de-deon elbows. most of our customers have carried on having mots as normal, so far all those that have thought about not having there cars tested have changed their minds when ive asked the following questions.
1, given two almost identical cars for sale which would you buy, one with an mot or one without?
2, if something unfortunate were to happen what proof have you the car was actually in roadworthy condition?
i know an mot isnt total proof of roadworthness and strictly only applies at the time of test, but a current mot certificate does give a car a lot more credit-ability. its also not a lot of money, being zero vat rated, in most cases its also cheaper than paying someone to look over your car, and a look over wont get you a brake test