Hello, This gun is described nicely in "British Secondary Small Arms 1914-1919, Part 3," by A.O.Edwards. If you don't have access to this British publication, I will be glad to send you a photocopy of the relevant pages.
You might note my posting of today about my British triple-lock being stolen at the Chicago airport. Mine is/was serial 4197 of the 5,000.
Mike Carrick, [email protected]