<i>"Mr Kingwell has been detecting for 25 years and has dedicated a room in his house as a museum for the items, which include four gold coins."</i>
It was my understanding that gold and other precious metals are defined as treasure trove and must be declared to the coroner.
I sincerely hope that Mr Kingwell reported these gold coins, and was subsequently advised that he could keep them as his own property, otherwise he's just admitted to a criminal act...