I wonder if you could argue that, with such a narrow margin, 57, your indicated speed, itself not perfect, will be affected by the tyre pressure. (i.e. the indicated speed will depend on the diameter of the wheel and hence tyre pressure).

Yes, but doesn't the 10% tolerance applies to all speed measuring gear and that includes the car's speedometer?

I didn't know what was going on. I sent an explanatory letter explaining that I thought I had been cloned twice before. (Cloners are only successful if they behave and don't attract attention, so it is surprising). This may or may not have been shown in court. They allege that the vehicle was doing 37 mph in a 30 zone. i believe that a 10% tolerance on measuring equipment is allowed (is this so?). This means that the speed camera could have been inaccurate and the car could have been doing 33.3mph

I got a letter from them asking who was driving my car about six months earlier. I replied that, after such a long time, I hadn't a clue. In my absence, they took me to court, gave me 6 points and a fine of over £700. === Are they allowed to wait such a long time before asking?