Quoting from the MOT Inspection Manual:
Headlamps’ colour must be one of the following:
white
yellow
mainly white light with a blue tinge
If a motorcycle is fitted with front position lamps, they can emit one of the following:
white light
amber light
mainly white light with a blue tinge
Rear position lamps must be red.
So these would be illegal, also imagine everyone having their own favourite colours on the front of their bike, it would look a road full of Xmas trees!