pezza - I sympathise fully with you. This is a highly controversial area, and is discussed in some detail on the Association of British Drivers web site.
http://www.abd.org.uk
I am very impressed by robber1's recollection. I am afraid I don't share his memory power, and I doubt if very many other people do either.
Good luck, I would imagine you have a valid defence, but unfortunately this obsession with prosecuting easy targets such as motorists has reached the stage where you are assumed guilty 'til you can prove your innnocence.