Well .... the MOT Testing should be based on the same criteria no matter of the testing station is also a repair centre or not. I don't think any station should be erring onn the side of anything really, but basing what they report on what they see.
I also think the point of the Advisories (or Minor Defects as they are now referred to?) is where items which are serviceable but would benefit from being attended to are noted - I don't see it as the role of a Tester to move something from 'Advisory' to 'Fail' because he is of an opinion there should be no defects at all.
I am not a vehicle mechanic and don't actually do very much in terms of mechanical work to my vehicles except, oddly, Brakes, so I would and do tend to accept the results of an MOT unless they are blatantly incorrect (such as 6 month/500 mile old Brake Discs apparently on the point of disintegration for example) or if the tester is unable to follow clearly documented (and publically accessible) testing procedures.
I don't think (as far as I am aware) that I have had an MOT test that has artificially failed a car in order to generate work. The nearest has been a old Peugeot 306 MOTed at Kwik-Fit and an Advisory given on brake pipes. We told them to go ahead and do the advisory work and replace them even though the car had passed already.
Now this may be interesting to you, Steve .... a couple of months after the MOT, the car was written off when it slid on black ice and hit a kerb and was deemed beyond economic repair (it was only worth around £1,000 IIRC). The
insurance company (the Co-op) actually agreed to include the cost of these brake repairs in the settlement as it was a recent optional repair (and we got more payout than was paid for the car initially). If it had been a repair required to pass the MOT, that repair cost would have been ignored I am sure.
If the MOT tester was of the mindset of "
I think this should be replaced, so going to fail it regardless of MOT guidelines", it would have actually cost us a couple of hundred quid