The ice wasn't the first scooter to have a plate holder over the rear wheel (possibly the first production one) but there are brackets out there for most scoots. although the sym jet had one that was perfect for the L plate.
fair nuff never really paid attention to make of scoots other than the main manufactures, although i did know that roxs dont have rear mudguars at all over the back wheel? i thought you had to have 'some' sort of guard by law?
i don't think there is a law stating that, the only specification is that the rear wheel mustn't stick out more than a set ammount so as long as there is something above it (in the case of most scooters it's the seat unit and rear frame). its available on the net somwhere but i cant remember the exact spec off the top of my head.