My tester has tested various cars with aftermarket hid lights, around 50% pass rate, so long as a correct beam of suitable colour is produced they can't fail it.
Headlight levellers and light washers are not part of the mot, my car has to go to mot soon without it's rear roll bar, but again it's a pass, as not tested, I'm having made some EN16T roll bars that clear the poly diff mounts.
Poly diff mount = AWSOME SPECTACULAR BEST THING EVER.
tabetha