[Billy Smalls]

I can only imagine an over-zealous MOT tester failed the period plates and modern plastic was the cheapest option...

Of course, in France (and I dare say other countries) you have to change the plate depending on where the car is registered, so often you'll have a beautifully finished Citroen DS for example with a hideous EU flagged plate....they don't even have the department flag on them now...