Any help would be greatly appreciated.
It appears to have:
the maker mark C & M;
a lion passant;
the number 18;
a crown;
and a sideways leaf with a capital E or F imprinted on it.
I had thought the crown might signify a Sheffield assay but this appears to be gold and they didn't start marking gold until 1904, and then it was with a different mark.
Anyway whatever help you can provide would be greatly appreciated.
Happy New Year!

there a lot of other photos that might be of assistance here.
https://onedrive.live.com/redir?resid=C ... =folder%2c