unknown marks

[david8]

can anyone help with any information with this coin inset snuff box and the hallmarks on the back of the box

[AG2012]

Hi,
These are not British silver marks.Moreover, it looks like copper or brass with patina.At least what images show;copper red color.
I cannot recognize the coin.
Regards

[david8]

thanks for your reply. maybe it could have been sheffield plate. David