I have pressed metal plates on my Clio - bought originally for my old M3 so German style font....
As you can see they had a "D" but our lass got pulled for that so then bought stickers to go over it, before that happened just put tape over for when they went onto the CSL...
You must have been lucky, that looks like Germany (the ring) i had my car impounded there because i had german style plates on my car and no english plates to refit.
Car was impounded until i could put legal english plates on (took 4 days to get some from uk) and a 500 euro fine