Ah, I see your point now and agree, in that context. Yes, the crown takes it. That said, if one is concerned about money rather than owning the items themselves, the english scheme is about as fair as it is going to get.
There can be another argument applied - finds such as this are singularly unique and, with proper study, can teach as much about the history of the time they were made as may be known now in some areas. If the owner simply can melt them and sell by weight, I might see some value in giving the state the mechanism to try to deter that. Making it so the owner gets paid the full amount they sell for or gets the items back if too low is far more that most would think a government would give. It is unfortunate that such a view as I offer above can be abused (or in the case of the spanish gold found and confiscated, simply used as a mechanism of theft), but that is what government does.
A find like this may not happen again in our lifetime, or this century, and is probably the most spectacular saxon dark-age england find ever that has survived or been recorded (presumably things have been found over the centuries that are melted). Assuming the finders get rational compensation (meaning a LOT), I don’t have a problem with the english law if the alternative is giving them the option to melt and resell, if that is their wish.