"The Crown had a prerogative right to treasure trove, and if the circumstances under which an object was found raised a prima facie presumption that it had been hidden, it belonged to the Crown unless someone else could show a better title to it.[25] The Crown could grant its right to treasure trove to any person in the form of a franchise."
So you didn't dig through the records to see if they have been seized. It belonged to the crown unless you could find reason why it should not. If there was no clear owner, it was presumed to be owned by the crown.
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.
Key words. If is isn't "treasure" it isn't subject to the act. Material belonging to British military units isn't treasure and remains property of the crown forever (basically all ship-related stuff). Anything else that once belonged to the crown still does. So if some lord buried a stash of silver and never dug it up, you may need to dig into family histories to determine if that lord's property had ever reverted to the crown. Treasure hunting isn't ever simple and you never really know if you can keep the stuff until long after the initial discovery.
Note too that the act speaks of "two or more" coins. One coin is treated differently than a find of two. This goes back to an older distinction between buried treasure and lost property. A single coin may fall out of a pocket and be lost. Two coins together are presumed deliberately buried or otherwise hidden.