The only suitable CC marks in Grimwade are Christian Claris (No 279 of 1727) , Charles Cotterell II (No 278 of 1723), and Charles Chapman (No 280 of 1734). Both the latter were smallworkers.
Claris , although a largeworker, as a Huguenot seems possible as the style is decidedly French I feel.
Cotterell was in Salisbury Court ( where several bucklemakers resided) after 1764, where the PR1773 recorded him without category.
None of their given marks appear to match this one which in which the letters seem very close to the edge of the punch
Found on a small buckle (32mm by 36 mm) in Baroque/Rococo style. Assay mark very worn or crude and could well be contemporary forgery but of the London 1720 —1740 type . The saddlepin is along the long side so it may be a large knee buckle rather than small shoe buckle. Like most surviving buckles of this period this is a dug item