Organize a appointment with a garage and tell the guy if he wants it for free to be there at x time on x day, then have the bill sent to you, not to him. then if the insurance company gets in contact you can show them the bill for works and he will be done for fraud by his own insurance company.
DONT deal in cash. <<<-------------------------------------------------
If he wants you to fix it you will fix it, if he doesnt, then insurance company will have to deal with it. Its not worth giving cash then him just saying you didnt. then your insurance going up as well, then you pay out twice
Edit again, also worth studying the road markings where it happened, and see if there were any cameras looking. shops may let you look at the footage for free, then you can see who was actually at fault, for example if he was pulling into your lane then its his fault, your lane, your right of way, if you were over the line into his lane, your fault. etc.