Reflector isnt a legal requirement but is needed for the MOT. Dont know about plate light but i dont have one and have never had a problem, you dont need one for the MOT.
if it isnt a legal requirement then why do you need one for an mot? you have just contradicted yourself buddy
you do need a reflector
cant find anything about a number plate light so guess its not a testable item
Statutory reflectors
Mopeds and motor bicycles require one unobscured red reflector which is aligned to the vehicles longitudinal centre line and is positioned to reflect squarely to the rear. If the motorcycle is fitted with a side car the side car will also require a reflector fitted towards the nearside and positioned to reflect squarely to the rear.
Reason for Rejection (FAILURE)
There is not one unobscured RED reflector (in the case of a motorcycle combination one on the machine and one on the sidecar) positioned to reflect squarely to the rear.