There must be enough clearance between the plate and the tyre so that when the rear suspension is fully compressed nothing touches/fouls the tyre, don't forget that also the tyre will expand at speed, so say 6mm gap when compressed to be safe.
I have just fitted a new brake light / number plate light and number plate bracket to my undertray to get through my retest, but how much gap is needed between the tyre and the plate?
