I know this one because it has been the subject of a dispute with my 4/4.
The regulations state that the registration plates must be
"... easily legible by a person standing approximately 20 metres to the front/rear of the vehicle". I can't find the link I used to have to the official rules, but they are also in the
MOT Testers' Manual. Note however that an MOT tester should only check that a car conforms to the spec of the car when it was granted type approval. The rear number plate of a 1980 4/4 4-seater cannot be read at eye level by anyone taller than three feet but that doesn't matter, they were like that from new. If you have an older car you need to make sure you take it to an MOT tester fully familiar with the rules!
~iw
