Some of the “blue chip” firms can even issue infringements for overspeeds over a couple of MPH over the speed the limiter is set to (even if it’s set to 52 for example, and you do 54). You can legally do up to 60 on motorways and dual carriageways. I bet that infringement you got was issued by some desk jockey fresh out of uni, and has never been inside a wagon before, never mind driven one, and knows jack (zb) anything about them!