All I have on him is Henry Trulock Harriss, 22 Bury Street, St. James, London 1909 to 1911. He was at 4, Pickering Place, St. James Street, from 1912 to 1916 trading as H. Trulock Harriss Ltd. reverting to just H. Trulock Harriss at the same address from 1917 to 1918. Depending on the title on the rib that should date your gun very closely. Lagopus.....