No firstly the car passed m.o.y without speedo working (they dont drive it down the road so not checked) and secondly i was stopped years ago in my old astra gte 1.8 when i had a speedo problem,,, i.e. i had fitted an exchange speedo as old one had packed up and forgot to flick the switch over to suit wheel size on car so speedo was reading slow like 13mph at about 30mph the old bill noticed this by driving next to me and i just told them yes i know there is a problem with it but i know that 13mph on my dash is 30mph really and they left me alone lol.....