Road rules

Hi Can someone help me? Back in May I had a collision with a motorbike. I was on a road indicating to turn left as I do each night. In front and behind me we other vehicles and no-one was moving more than a couple of miles an hour as the traffic was heavy as always. I checked my mirrors and up ahead - no vehicle we coming towards me on the other side of the road and behind me (the traffic was stationary behind me). I indicated to turn right, checked again - was just turning the wheel and a motobike overtook the cars behind me, on the wrong side of the road and collided with me. He came off his bike - I immediately pulled over and asked if he was ok, if he wanted medical help or if I should call the police . On both counts he replied no - he asked me to help move his bike which I did. My workmate stopped after seeing me pull up - no one else stopped. My workmate asked the guy if he was ok and he replied fine, had gashed his knee and elbow. I then returned to my car to get my insurance details..he gave me his mobile to call for his later. He then rode off. His bike was scratched, my wing and wing mirror were scratched. I got back home and got his insurance details. The matter was left with our insurers. An investigator visited me and the accident site - asked me to go over my account of what happened. He left happy with my account. Today I received a letter from the guys solicitor saying they are going to do me for driving with undue car and attention. I don't believe I was driving without due care and attention - he overtook stationary traffic on the other side of the road, I was indicating and he went into me?? I'm scared of what's going to happen - I've never had points on my license. I've never been involved in an accident before. Will I go to prison? I don't know if I sound a bit OOT but I really have no clue as to what to do next??