My old plates on my previous two cars were almost identical to yours buddy, I traveled through Spain, Portugal, France, Italy, Switzerland, Germany and the Netherlands, used Portsmouth, Plymouth, Dover and Newcastle as points of exit and entry in the UK, Santander, St Malo, Amsterdam (Ijmuggen??), Boulogne sur Mere and Caen for exit and entry to Europe.
Have done Le Mans a few times, trips to Bordeaux to visit friends, probably covered close on 20k miles in Europe over the years, with nearly the EXACT same plates, not one second look by any police, border control, traffic cop, anyone in authority far less, "why you no got blue Euro thingy?"
I wouldn't worry about it mate they're perfectly legal, and the number plate police have, obviously all died and been resurrected on here!!
Nice plates buddy