Alan,
I had an incident similar to this about a year after I learnt to drive. Glancing blows on a narrow lane. Both agreed at the time to fix our own, having passed details of course.
1 1/2 years later, I get a letter from my old insurance company saying that someone had just filed a claim against me. Turns out it was this old boy. I was so young and stupid at the time I basically rolled over and did not question it. lost my no claims, 50/50 incident on back lanes, and didn't even gain the cost of the repairs I had already done on the car!!!
I was not happy, and given K14 Sup (Sorry don't known name) comments regarding deception I would fight the hell out of it.
Why leave it soooo late!!!!