By “over there” do you mean the UK in particular or Europe in general?
I have no current experience, but I do know that in the 80’s in France and Italy, they were shutting down farms whenever anything was found.
I believe its the UK. I don’t know which countries adopted the current treasure trove laws.
Some pressure to adopt this treasure trove law must have been happening in the 80’s. I think that they were having a real problem with people smuggling artifacts out of the country. People would hunt for treasures in the middle of the night (night-hawking). There were several instances of someone attempting to keep and smuggle Celtic gold coins.