ok, so it arrived and well as far as I can see the bellows are light tight. Its made by lancaster & Son, Birmingham. Lens says Lancaster Patent and has an aperture (10-30 - labelled in time as 1-8 - what does that mean in modern apertures?). Seems to be (guess) a 9 inch - will check. The half plate ground glass has been bodged into a quarter plate one recently (MDF edging). - where is the best place to get a new one or should I just make one? Whats the best thickness for gg? Another odd thing - lens looks like its missing its front elements - could be I have half a lens I suppose... From the (penny red) stamp on the original packaging it looks like it is from between 1841-1864 - if I check the perforations might get a better date.