There is an interesting exchange of letters with the scameraship in the unsigned forms group. In particular the point is made that there was no way to tie up the calibration certificate wth the actual equipment with that used at the time of the offence, see :
http://tinyurl.com/yt22g
I used to work for an ISO9002 registered company and we had to pay particular attention to the equipment calibration issue as part of our compliance. I have thought for a long time that the Police and Scamership calibration issue would bear expert examination in court. I am not a calibration expert, just someone who had to comply. If anyone out there is an expert out there I would think it worth a go. The case would almost certainly have to go to appeal as the lower courts appear to have a "convict at all costs policy".