Treasure Hunting, Like Shooting Fish in a Barrel

This story has everything: love-interest, bling, money and a gory death - making it ideal for BM dumbdown story telling, hence the BBC news item ('Lost ' medieval gold brooch was 'gift from beheaded baron'). In Leicestershire castle a medieval gold brooch believed to have been lost by a baroness more than 500 years ago has been found near the moat of Kirby Muxloe Castle.

The 15th Century heart-shaped brooch probably belonged to Baroness Hastings, who lived in Kirby Muxloe Castle. The jewel, found by a metal detectorist in a farmer's field, will be sold at auction in August. Experts say it would have been given to her by Baron William Hastings, who was beheaded in 1483. The brooch has a guide price of £6,000-£8,000. It is inlaid with white enamel and engraved with the medieval French inscription "honor et joie" (honour and joy). The finder, who wants to remain anonymous, will split the proceeds of the auction with the landowner after the British Museum declared it treasure but declined to purchase it. [...] The jewel was examined by experts at Hanson's Auctioneers and then authenticated at the British Museum. 

I am sure he's joyful about finding it but if the finder had any honour, he'd not be taking a cut of the proceeds of selling off a dead woman's lost property. Um, why was it reported as only handed to the BM after valuation by Hanson's?  his Treasure hunting game is like shooting fish in a barrel, find a known high status site, get a metal detector and hoover away all around it, you are sure to find something if you dig deep enough.

Are there any descendants of Katherine Neville, Baroness Hastings, alive? Perhaps they should have first option on what happens to this?