Not much I’d imagine though I did hear of a pair of detectorists getting prosecuted having found a lot of Viking stuff which they hadn’t declared and sold.
The best example was The Mildenhall Treasure. A farmer tried to crack on that a huge silver find had been in the family for generations. He lost it all and kept out of the jailhouse by the skin of his teeth.
@stopmeandslapme I was wondering why you'd gone quiet https://www.ancient-origins.net/news-history-archaeology/celtic-coins-0014729 Metal detector + bird watcher, what a catch <corduroy>