IMPORTANT....Don't tell the reputable garage what you want the written report for as he may play things down if he knows what it's being used for and also a lot of garage owners piss in the same pot if you know what I mean.
I did the above with a landrover and got full compensation plus a load extra as well for all the stress and inconveniance.
I had a series 2 landrover and the handbrake on those works by a simplistic method of a clamp locking around the propshaft. Unfortunately, the way garages MOT test handbrakes for modern cars is to operate the car in gear with the handbrake on to see if it holds back the car motion. Disasterous on an old L/Rover with a braking shoe that clamps around the propshaft. Screwed up my shaft and my transmission. They said it was my fault for not warning them but I'd assumed they knew what they were doing. Cost of rectifying it was 400 quid. At the small claims court I was awarded 1,300 quid
