That was back in the 19th century and earlier though. From around WW1 it became default practice to pay the full value if a museum took it, or return the items

That was back in the 19th century and earlier though. From around WW1 it became default practice to pay the full value if a museum took it, or return the items to the finder if not. The 96 act added nuance and the split with the land owner. Mainly, I think, thanks to detectorists finding stuff on land that was someone else's.