I’d note it’s an illegal plate and an illegal font which you can spot a mile off. Probably just an excuse to get pulled. Don’t go to Wales.
Or East London 
The cop cars you’ve driven past probably haven’t been traffic officers, local officers definitely wont be bothered to stop a biker with a small plate trust me 
The traffic officers can be a strange breed, just as likely to give you a ticket and go to town on anything else they can find or just give you words of advice !
It will still be picked up by ANPR camera’s, not sure about speed camera’s to be honest.
.
Its a 2007 Fireblade…I have normal font though which I think is important. It might be the 7 x 5 size …even when getting stopped for other stuff Ive never had a comment on it
Basically what the others have said. It is a illegal plate as the ANPR cams cant read it therefore you will be tugged and as its not the legal size its asking for trouble.
You may find the cops in london have far more to worry about than your illegal plate but you try riding in the surrounding counties and you will get pulled for sure.
It is illegal and yet you carry the full size with you? Why?
Just take that off and fit the correct one. Or at least if you want to fit a smaller plate make sure the font is correct and a decent size. Then you may get away with it.
That’s what I did
Normal font, slightly smaller plate (about 1" x 1" smaller)
haven’t had any issues yet but then it’s probably not that obvious unless measured
just to clear up something ANPR can read smaller plates …
As i said, i only bought it a couple weeks ago with the small plate already fitted, stuck the paperwork and full size plate in my bag then rode from Oxford back to London. Havent got around to changing it yet and the plate is still in my bag.
I intend on swapping over at the end of the month when i change the tyres but no problems so far so wondered whether it was really worth it. I didnt go to the trouble of sticking the plate on myself.
Plates like that are asking for a tug. One of mine is a little smaller than “legal” and has a standard font shape it’s always got through MoT’s.
It’s not the worst I have seen. There are plenty of one line ones about that are like yellow dymo tape!
That’s a bit borderline IMO, not letterbox bad but hard to read from a reasonable distance. I’ve had 7x5 on my bikes forever and never been pulled for them. As somebody said above, London police won’t care but forces from the surrounding counties might take a fancy to it…