Its quite rare, I have only seen 2 others with it while at shows, I saw a hire van parked up once with one
No but I believe not having one may be an MOT failure, I think you missed the clue above, would be an MOT failure without it
Something to do with a fog lamp? that's the only Mot failure item I can think of in that area that's an add-on but why the hole... curiouser and curiouser