I have no information about this particular coin or who/where you bought it from.
But I will say that several "dealers" from UK (and also from the Netherlands), mainly people who list on
Ebay, use "local metal detecting find" to obscure the real origin of coins.
You can tell this by looking over their entire listings. While a few odd coin finds have been officially documented in the UK through the PAS system - including
Ptolemaic coins,
Byzantine coins, Greek Imperials, etc. these are very few in number. When a dealer claims UK detector find but their stock consists of
Byzantine,
Greek Imperial from Balkan cities,
Roman Imperial all from Balkans mints, and East European
medieval coins - they are lying. Those coins were not found in the UK by detectorists.
Again, I have no idea of the details of this case but don't be fooled into believing that by such claims are necessarily true.
SC