I am attempting to identify the maker's mark on some sterling flatware marked London and 1858-9. The maker's mark is SH over DC. It is not in Jackson's, the other two books that I have, or in any online resource that I have checked. I have been unable to locate a copy of Fallon's book Marks of London Goldsmiths and Silversmiths 1837 - 1914. I'd appreciate any help you can provide.