That's a fair result in the end and I'm sure he'll buy you a few beers for your efforts.I suspect that we won't be seeing StephenHirst here any more, since he's binned the S3 and bought a 330 M-Sport instead.
To update on his behalf though, Stephen got in touch with me and we discussed the issue and circumstances for a brief period. I then drafted a letter for him to send to Audi UK challenging the lack of any proper root cause analysis and asking for clarification on how they can refuse a claim based upon ECU data points that lack credibility.
Audi replied to Stephen 4 days later. While they didn't offer any explanations on why or how the data points can be recorded, they did offer to pick up almost half of the £5.5k bill for the repair, an offer he accepted.
Just goes to show, you should never-ever take the dealers word for it, and even when all appears lost, it never-ever hurts to ask.
That's what I like about this forum, there are people willing to come forward and help others in their time of need.