Erm, I wasn't trying to get into an argument, but whether or not there is an issue with HIDs (and I don't think that's the same thing at all, I think you may be confusing the factory fitting of OEM HIDs with what gets tested at MoT time) it's not something that stands out as glaringly obvious to any passing policeman.
The spacing on your number plates is clearly obvious for anyone to see. Changing it is illegal. Why change something that practically shouts out "please stop me and give me a fine" ? You're giving the police a perfect excuse to pull you over if they feel inclined to (and perhaps check other things on your car at the same time ?).
I agree that perhaps the law on this is perhaps a bit silly, but it is the law after all.