Cyclist Touring Club
A venerable institution...
http://www.ctc.org.uk/ but not much good if you're not in the UK...
@BBP - did you get the contact details of the independent witnesses? This will make your case a lot stronger if they concur with your side of the story.
I carry a small business card with me with a list of reminders of what to do in the event of an accident. Shock, pain and the strange euphoria of walking away (hopefully) from an accident can do funny things with your thought processes.