J. Gavin Scott, in British Countermarks on Copper & Bronze coins lists a (Crown)WC countermark on a penny 1797 sold by H. D. Gibbs, sale 1960, lot 456, under catalogue number 123-403 with the following footnote:
See 123.10 above. The piece was attributed to West Coast, Sierra Leone, in the Gibbs sale. There is no documentary evidence to support the official countermarking of copper coins with this mark. Pridmore discusses the West African countermarks in depth in Sink's Numismatic Circular, February 1954, columns 59-64. The piece is either a concoction, or, more likely, a brand mark.
The footnote at 123.10 referred to is as follows: It was common practice in the nineteenth century and earlier ti incorporate a crown in trade and brand marks. This was particularly common in the metal trades, but was not confined to Sheffield, which, from 1773, used a crown as its town mark on silver goods. The Trade Marks act of 1938 prohibited the use ofBritish Royal or Imperial Crowns in trade marks.
A common pitfall is to attribute such countermarked pieces to the West Indies. It should also be noted that copper coin was disliked in this area, the natives preferring silver and billon. Some of these pieces may have been used as shop tickets.
I think the conclusion: "concoction or shop ticket" is warranted. Personally, I have a preference for the first, as I can't see a shop countermarking a coin that has already been countermarked by one of its competitors, but it remains possible that the two brands were connected in a non-competitive way.
Intriguingly, Gavin Scott reports a countermark W. Cox/C (no crown) on a penny 1797. There is no evidence to link this stamp with 123.403, though.
Peter