Karma? c`mon dude, im sorry to say but not everyone believes on the same theory as you do..
We all dont know what the conclusion is to his part, he could of been buying his insurance tomorrow? next week?...who knows but it is definately questionable.
Also you probably meant question from the lawyer.
Im pretty sure Fuz888 is "reasonable" enough with his situation, it is pretty clear that the car wash company is responsible upon his stolen vehicle the moment he walked outside and saw the car in the queue while he goes and get a kebab. Even if he returned late while expecting his car is done, the time span of him being away already justifies that the car is still under their care. The only scenarios i would think of is that, since they had his keys it may have been stolen off them, which they will then be questioned about their workplace security. OR someone portrays to be him, which questions their customer confidentiality. but yes i agree it is very limited.
Anyway all the best fuzz, let us know your progress.