Here's a couple of things about European airgun power laws...
First the Brits are actually shooting guns with more like 11 Ft/Lbs than 12. That's because the law says that the air rifle must not be capable of exceeding 12 Ft/Lbs under any circumstances. So some headroom is required. The gun cannot be set for -say - 11.9 Ft/Lbs and risk that a heavy pellet just breaks the limit, if tested.
Also that 12 Ft/Lb limit looks pretty generous compared to the limit for airguns in most European countries. These have a limit of 7.5 Joules - that's about 5.5 Ft/Lbs.
True there are no power limits for airguns in the Netherlands - so far as I am aware. And no power limit in Denmark so long as you use only .177 caliber.
But generally most European countries are even more restrictive than the United Kingdom