I saw your posting from 2001 about your box made by H Summerscale.My note may no longer be relevant, but I have some input on this family.
I agree with your conclusion that the maker of the box was Harry Summerscale, son of John Summerscale the upholsterer.
I am doing research for a best friend, Claire, who is direct descendant of Percy Summerscale (b 1875), a younger brother of Harry the box maker.Percy was a school teacher and had one son, and there are many living descendants, some called Summerscale.
I have not pursued Harry the box maker much but he married a girl called Florence Hartley 1888, and they had at least one child, also Florence.
I know quite a bit more about the earlier generations of this family (strong emphasis on cabinet-making) and am still on the trail.Let me know if you'd like to know more.
I tried to email you off-line but your address seems to have changed. Best regards Celia Moss London UK