Does he get to keep or profit from his prize? Because from what I’ve read, all such things have to be turned over to the government.
In the video it's said that they split the proceeds with the landowner. Don't know what are the applicable laws.
"The Treasure Act of 1996 is an Act of Parliament designed to deal with finds of treasure in the England, Wales and Northern Ireland; it does not apply in Scotland[1]. It legally obliges finders of objects which constitute a legally defined term of treasure to report their find to their local coroner within fourteen days. An inquest led by the coroner then determines whether the find constitutes treasure or not. If it is declared to be treasure then the owner must offer the item for sale to a museum at a price set by an independent board of antiquities experts (Treasure Valuation Committee). Only if a museum expresses no interest in the item, or is unable to purchase it, the owner can retain it."
From most accounts that I've read, most are satisfied with the money offered.