I dont know if anyones suggested this already as i only had a brief peek through the answers. But you dont have to go through insurance, now i know the accident wasnt your fault. But to protect your ncb you can deal with his insurance company directly, so you pay the for his car to be repaired (or the 50/50). But i know since it wasnt your fault you probably wont want to do this, but it is a thought if it protects you ncb it may be a better route. You would have to do your renewal sums etc to see if it is worth while. Out of principal i would fight it, but its another option