having been an MOT tester for years, (not going to say how many!!!) this has always been the case, too many grey areas and how one person interprets the pass and fail rules. They ministry will look at this in 2 ways, normally if unsure, you used to pass and advise it. However, from what i gather that has now changed to fail it, purely because everyone is scared of loosing their tester ticket or getting sued!
When they first bought in the 30cm rule it was chaos! Prior to that it was simple, ANY holed corrosion on structural areas (floors,sills, cross member etc etc) was a fail! Simple end of. Then all of a sudden you were passing cars with holes in the floor, because it was NOT within 30cm of seatbelt or suspension mounting points. 20 years later...................it's still clear as mud. The one i just bought has a hole in the crossmember, 2 MOT stations confirm it is NOT a failure as outside the 30cm rule. Yet, personally speaking, i'd say it was a failure!
I remember once being told by an inspector a few stories. One, that a rear number plate light had to work.....it did NOT have to be attached to the car, it could be hanging off, but as long as it shone white light to the front, it was fine, and 2, it didn't even had to light up the number plate!!!
I was also told that if you failed a car on a fuel leak, say tank had leak at the top, customer took car off premises, and in front of your eyes drained the tank down below the leak area, then still with you watching, presented it for retest, you would HAVE to pass it!!! this was all due to the rule 'as presented'. For many many years the construction and use regs, and the highway act and MOT rules have worked against each other.
You could very easily pass a car that was ok for the MOT, but was illegal to drive on the road................bloody madness!
But heh..................i remember when you never jacked up the back of the car, only checked minimal lights, (if they were fitted at all) and MOT's took about 15 minutes to do!!!! Showing my age i know!