Can be an interesting exercise to guesstimate the repair cost at which it's +EV for the young driver to pay for the other drivers repairs directly rather than go through the insurance.
If the repairs were £700 or less I'd probably choose the direct route.
Once its reported though you have to declare it as an accident whether you claimed or not. Losing your no claims bonus would be a hit but if you don't have any yet.....
If they're going to penalise you for having a crash anyway you might as well get them to pay for the damage.
Far from an exact science isn't it