I don’t think the U.K. will ever have an aires system like France ( and the majority of Europe) certainly, in France there is a proper Right to Roam and wildcamping ( however you define it) is acceptable and quite common, as long as the facility is not abused. There are also very very few interfering busybodies who enjoy telling you you can’t sleep / stop there or contact the local paper telling them they have seen you emptying your cassette/ leaving tons of rubbish around.
But, even in France, restrictions are being put in place in some areas and aires are closing down or being moved away from coastal towns and beauty spots, reasons given are that areas are becoming congested with wildcampers or local roads in tiny coastal villages are becoming congested by large motorhomes.
This has happened along the south Brittany coast where many of their aires were closed during the summer.
Portugal and Spain are also clamping down on wild camping, especially where dozens of vans congregate on beaches and other busy tourist areas.
England, unfortunately, has no real right to roam and Wales has implied ( or by now probably legislated) that wild camping is illegal.
It’s really nice to find a remote spot somewhere nice and quiet with great views and spend a night or two there and I envy you if you can, and long may it continue, but, I am guessing they won’t be around for long as soon as a busy body member of the public spots you……