Thanks everyone for your replies, the majority of which are for me to do the right thing and give the statement.
I will sleep on it and decide tomorrow.
If it was me in the accident I would like to think someone would do the same for me.
Last August, I witnessed a car v motorcycle accident, so stopped in case First Aid was required. I also gave my details to one of the involved parties as a witness.
I provided my version of events, giving a description and drawing of what happened which I kept very factual. I have my own...