Having been caught with my pants down before (ebay not HGM), I took an interest in fakes/counterfeits.
The reasoning behind their manufacture is interesting. Believe it or not, at one time, a bullion sovereign was worth more than its weight in gold!
I have an interesting article that I'll post in full in the Premium Lounge.
'The Italian coins, probably mainly from Beraha’s organisation, were found to usually contain between 91.2 to 91.7% gold whereas the Syrian/Lebanese coins, attributed to Chatile and others, varied between 88.0 to 91.5% gold.'