Should have done something about this sooner. Too late for one sidelight, and the other one is pretty far gone too. I can probably get away with replacing these with cheap bicyle light covers, at least if I stay away from government inspection centres, but the other light covers may not be replaceable. I'm thinking maybe cover them with Clingfilm (Saran wrap in the US?) and maybe cover the car when not in use, which is most of the time. Any other suggestions for protection? I wondered about casting replacements from a clear resin, but that's likely to be very difficult even if I could get the stuff.