Bruce gurgled happily, sounding much like they
were saying:

Perhaps the government decided it was worth it for the reduction in
hassle for the owners and less beaurocracy being required if the plate
stays with the car for its entire life.

There's absolutely no reason why the old style plate couldn't stay with
the car for its entire life.

Providing that car stayed registered within the same dept.

Besides, possibly some people may prefer the anonymity anyway. Parisians
arn't all that popular in some parts of france and perhaps they'd like
having plates that don't give way where they're from.

That's true. You would need a more detailed knowledge of the British
registration system to detect cars that are registered in London.

The big difference, of course, is that a car with an Lx-for-London plate
needn't ever have been registered to a London address, just that it was
initially registered through the DVLA's London office. A French car with
a 75 (or 92/93/94/95 if we count the surrounding areas to Ile de France)
plate is currently registered to an address in those departments.