One of my favourite perfumes when I was in my late teens was Dioressence by Dior and in those days, the late 70's, this included natural ambergris.
So what is ambergris (grey amber in French)? Ambergris comes from sperm whales; the whale secretes a substance to heal its stomach from the scratches of the cuttlefish it swallows when feeding. This gets out through the gastrointestinal system and is left floating on the ocean for years, the longer the better. It is like a good maturing process! A well matured ambergris has a characteristic slightly salty and warm, sensuous smell. This scent lasts for centuries, just like musk. In addition, ambergris has a remarkable ability as a fixative for less lasting perfume notes and makes them last a lot longer.
I suspect strongly that the piece found on Anglesey is quite new as the reporter finds the smell of it unpleasant. I am guessing that whoever bought the piece will now leave it to mature for several years before it is used in perfumes.
Natural ambergris is very rare and these days synthetic versions are used in perfumes. Only top-end, exclusive perfume houses and perfumers include natural ambergris, like my heroine Joy Chabrier in Joy's Story.