We’re in Bas Rhin currently and the 30kph limit seems to be universally ignored by French drivers, although the speed humps force you to a crawl unless you want to lose your pillion. 20mph is a stupid limit because internal combustion engined vehicles are not designed to travel so slowly. The gearing is not designed for long periods at this speed, they overheat and cruise control doesn’t operate. Bicycles will overtake you, people will routinely pull out of side roads in front of you because you appear to be (and are) not making adequate progress, and the speed reduction from 60mph to 20mph is far too abrupt. The environmental argument doesn’t hold at such low speeds because wind resistance isn’t a factor and running at 2.5krpm in 3rd is unlikely to use less fuel than 3k rpm in 2nd (and there are bikes that will be in 1st at 20mph - how wonderful is that for fuel consumption and noise?).
Drakeford simply wanted his legacy to be the first to introduce 20 mph throughout, and found justification in a crash test dummy report comparing injuries if you stood in front of a car doing that speed instead of 30mph. No consideration was given to reducing the number of people who stood in front of cars or the practical impact of the speed reduction. The problem is that once introduced, the limit can never be raised. It is irreversible because which politicians will vote for more deaths or injuries? Western society is becoming victim to its own virtue signalling and I can’t see a way out of it other than moving to Hungary!