I really must learn to gather my thoughts and get my comments into a single reply rather than re-appearing with a series of postscripts. Sorry about that. I just want to add, in case anybody comes back about this, that I am aware of a passing resemblance between the outline of the cartouches on these marks and that on the marks of what David Murray has named the Cape Stub, see the Finial of May/June 2007.(admin edit - see Posting Requirements )
I don't think that points to a Cape connection. The Cape stub has a unique and unvarying group of four pseudo marks. I am not aware that their outline matches any other known Cape marks. I do notice that the marks here seem to be within two stubs: one with the initials C.G and W, the other with the three pseudo hallmarks. That presumably means the workshop had enough business to justify getting these specialist dies cut. I might speculate whether they were commissioned for use with a similar press to that used by the proprietor of the Cape stub, but I don't think it is any help in trying to pinpoint the location of the silversmith.