Eddie, just curious, did you get stopped on both occasions because of your small plate or were they simply doing random stops, and you got unlucky?
Both instances I was aware of them before they saw me and was riding accordingly.
The London stop seemed entirely random - 7.15am they must have been just bored. No other reason to stop. Did not inspect bike. They just saw small plate and bingo!
The Hampshire stop was on a pleasant weekday afternoon and a traffic car was parked up. Stopped politely and again only discussed the plate.
Like I said, there's no consistency in how they handle this. I'd prefer it if they rigidly enforced this particular law then we'd all know where we stood.
Why don't they stop the yuppies who couldn't afford a decent personalised plate but attempt to make 13 look like a letter B?
Or the gang bangers driving BMWs with whacky typefaces that you cannot read?
A week after I replaced my plate for the legal one I was parked up next to lovely R1 with a french-style bike plate on and the rear end looked gorgeous. Will that guy get stopped and made to change it? While I hope not, it did peeve me that I got tugged twice for a considerably larger plate.
I would take a guess that most bikes plates do not comply with the law, and many, many 'personalised' plates on cars too. The rules are quite exact:
http://www.dvla.gov.uk/vehicles/regmarks/reg_marks_current_requirements.htm
Many of you with the dealers name on the plate, a GB or other sticker, or incorrect spacing fall foul, as do those who, while trying to make the plate look cool, split the characters into incorrect groups.
Good luck if you decide to tinker with your plate. I won't because as has already been pointed out it attaracts unwanted attention. But I long for the day that I move to France and can live a little easier on the roads.