Here's a photo of a drawing of the scarce porcelain oil reservoir insulator made by General Electric Co., LTD of England found in their wholesale catalog circa 1915-30. Apparently they had manufacturing works (for all their numerous products including insulators, dynamos, tools, fuse wires, etc) in London, Birmingham, Manchester, Coventry, Southampton, Eastleigh, Erith, Northampton, and Lemington-on-Tyne.