As he is the resident halfpenny expert this is probably one for Rob.
There's a 1717 copper proof halfpenny I've owned for some years which has an inverted reverse. Other copper examples which I've been able to find online all have an upright reverse and do not die match with my coin. The only perfect die match I can find with an inverted reverse is BMC 771 but all those I've found are in silver only. Does anyone know of others matching BMC 771 struck in copper?
Thank you.