Looks like a London Lion Passant Guardant and a date of 1795/96.
I suggest that the makers mark is probably Roger Biggs's smallworker mark of 14th May 1791 (Grimwade nr 2273) . He registered further marks as a goldsmith in 1822 and 1826, indicating perhaps his main trade was small items of gold jewelry - which seem to fit this article.
What size is it please ?
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Thank you "buckler" for that information.
As to the size, each arm of the square is 3.75 inches (max dimension), and the distance between the two points is 4.75inches.
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