Would appreciate some advice
on following problem and legally where we stand. We carried out a MOT on a 2008 Audi A6 2.0Diesel engine code BRE. The tester had completed the emissions test in which it passed, whilst the emissions report was printing the tester went to the rear of the vehicle to remove the probe from the exhaust as he was extracting the probe he heard what he thought was a diesel knock from the engine. As started to walk back to the drivers seat the engine suddenly revved up and before he had chance to switch off there was a bang and yes you guessed a Con rod had let go through the block. After some investigation oil had got through the induction system and intercooler and engine had run up on the oil. The turbo appears to be Ok as in the shaft spins and there is no play in the bearings. What we have noticed is although some oil was dumped on the floor the oil level is still showing max. The oil is very this and smells of Diesel. We are of the opinion the oil is contaminated with diesel and some how a failure has occurred during the emissions test to dump excess fuel into the sump. We have checked for any fault codes but nothing showing. Having spoken to a couple of people items such as injectors have been suggested as possible cause. Also another suggestion was a faulty Tandem pump apparently these can cause fuel to enter sump causing high oil level. Appreciate any
Feed back both technical and from a legal prospective as naturally our customer is pointing the finger at us and holding us responsible again any help appreciated.

Regards
Dave