Bugger! Got caught by a fixed GATSO doing 55 in a 40! last week. I know because the paperwork came through today. My own fault really. I knew the camera was there...just a momentary lapse in concentration - and BANG!
Interestingly the Notice of Intended Prosecution doesn't give the option of paying the fine straightaway - they simply say they are going to prosecute you and you this MAY mean a fixed penalty!