The way England has it set up encourages the detectorists to find stuff, the government has to pay the appraised value. And iirc, the detectorist and the farmer (or property owner) can come up with their own agreement on the split so it isn't necessarily 50/50 set by the government.
And by “first dibs”, the government doesn't want everything that is found - only if it is culturally significant.
I can't imagine that these coins from the 1700’s would be that significant to have in a museum.