Hi Tony,
I have looked up the firm of Ross and have discovered that a T Wayland has done a study of the company called Ross of London Chronology.
http://home.europa.com/~telscope/Ross/Ross.of.London.chronology.by.T.Wayland.pdf
A most interesting piece of history was disclosed in the document. A sideline note beside the date of 10 December 1920 tells that Sir Charles Parsons was the Son of the Earl of Rosse. Sir Charles was elected Director and Chairman of the Board of Ross Ltd on February 1st 1921.
Unfortunately I misspelled the Earl's name, it Should be Rosse, not Ross. There is an Earl by name of Ross in Scotland.
YouTube has an interesting piece called Lord Rosse's Great Telescope 1967, which was an interview which the Sixth Earl of Rosse gave to Patrick Moore, Astronomer detailing the work of the Third Earl of Rosse born in 1800 in York and died in Monkstown, Dublin in 1867 after having built the world's largest telescope, the Leviathan, a 72" metal speculum (2 parts copper and one part tin) metal mirror reflector which has been restored and is still in place in Birr Castle, Co Offaly in Ireland .
Back to the camera/projector, of whatever it should be called, I have not found any images of a Ross 9 1/2" Apo Process f9 Xpres lens on the internet, but I shall keep trying.