It shouldn't, as long as it isn't impairing light output. I'd be inclined to put a piece of helitape or similar over it to prevent water ingress and subsequent future degredation though.
Pictures of the small crack. Due for MOT next Wednesday. Doesn't seem to effect the light pattern when I looked last night but I know certain places can be picky.
Edited by Moley RUFC on Saturday 15th February 08:45