I think it would be unfair to name the dealer at this point as the problem is apparently with the ECU itself (it ties in to the problem they were trying to solve). As Gamba said it is pretty hard to trash an ECU so at this stage I will give them the benefit of the doubt.
I have been given a decent replacement car A6 SE diesel CVT. The CVT gearbox is bizarre, incredibly smooth, almost impossible to notice the 'gear' changes it just seems to gather speed.