Re: Audi Service and Dashcam
If no files have been written to the card since they formatted it (or even if they have), you could try software called Recuva :
Recuva - Free Download
Install it on your PC and point it at the card - it will suggest to save any recovered files to your hard drive instead of back to the card, so as to avoid destroying other recoverable files.
What you'll find is anyone's guess, but it will be interesting to find out what they were trying to hide...
Re: Audi Service and Dashcam
Recovered deleted files. There's about 15 min of footage, before mechanic realised there's a dashcam and disconnected wires. Nothing extraordinary - the "worst" thing I've noticed was that he was getting inside few times and put protective seat cover just some time later, that's it. No idea why they formatted SD card. And I really don't like they did it without letting me know.
Re: Audi Service and Dashcam
Personally I disconnect mine and take then down after I arrive at the garage, but I too would be miffed if they did that to me.
They might have been concerned that other customers' personal details might have been picked up on the microphone? On the other hand, once they messed with the card they could be said to be in breach of the Computer Misuse Act. It's not a part of the car and you didn't authorise them to access or modify the data within.