A week ago I forgot to apply the hand brake when I parked the car when picking up the kids from school. When I returned, the car had rolled forward maybe 2 metres into another car. I reversed and checked the other car - thankfully not a scratch on it, which I guess wasn't surprising as the road was pretty much flat so the impact must have been super slow. Didn't want to run off without saying anything, so left my details on the car windscreen and said to contact me if there was any problem.
The owner called me the next day, hadn't seen any damage. Then he called me again today, said he's taken it to the garage and that the car has a cracked bumper (£250 + VAT to fix) and needs further investigation to see if it has a damaged axle and some other stuff. Expects me to pay it.
Now, I'm happy to pay for any damage I caused (well, not happy, but you know!) ... but I'm wondering if this guy is taking the piss. There was not even the tiniest mark on the car - 2 people witnessed the whole thing and one of them ran his hand over the whole area afterwards, had a good look, and declared all was well. So, the idea that there has been 100s of £ worth of damage caused makes me a bit 
The owner gave me the phone number of the body shop where he took it so I can speak to the guy who had a look, but I haven't called yet and not sure even what to ask ... I mean, even if the car's damaged, how can anyone know it was caused by my car? If it had been an indentation matching my car bumper, then fair enough, but this is all a bit odd.
Interested in honest reactions to this, please. My natural reaction in situations like this is to feel so awkward that I will just pay up, but also trying not to get taken advantage of.
Also ... any suggestions about what to ask when I do call the body shop would be welcome. Thank you 