As said on Sunday, if it was me, i would put a complaint in to Vosa. Or at least contacat them re the complaints procedure. If your an AA member i would be in touch with them for an independent report. Thing is, most issues will be hard to prove, but the rear shock is fairly cast iron proof imho, if you have the receipt for the shock and labour for fitting it.
For info, the car has a Monroe shock fitted, it is not self levelling. The air pipe has been cable tied up to the fuel filter and left to vent freely. The other is standard self level and working fine all be itwith the air pipe stretched tight with no slack.
Result is about 2.5 inches difference in ride hight between the rear wheels. The car has presumably passed the MOT in this state. When 2am followed me to my house, i could see that the car was not level from my rear view mirror.
In all honesty i was more concerned with the rough running when 2am arrived, having seen the shock and the rear box I am very suspicious. 2am also sounds like he was over charged for the Brakes fitted.
Will post all pics taken in a mo if the lapy ever fires up.