That's a good point - I doubt the MOT tester would check that the appropriate CE marks were evident, and they wouldn't dismantle to see if they were removable LED bulbs (I assume that the dedicated LED units have a fixed bulb - more like sealed beams).

1972 4/4 4 seater, 1981 MGB GT
1984 Harley Davidson Electra Glide, 1990 Kawasaki ZX10