Thanks wannab,
A few glasses of red wine, and I actually bought both the Mobieus kit and the projector in the last 10 minutes. If what member "Valor" says about his projector purchase is anything to go by, the lens glass is 70mm in dia. I expect the lens in the Haimex I just bought is probably the same.
It might be a Frankenstein type of situation, my brother and I will try some mixing and matching to see if we can perhaps enhance the Mobieus kit etc.
Ultimately my intention is to build a dock for Hal along the lines of the company (whos name I dare not mention at this time) made and wire up a bluetooth speaker, charging ports... food blender?.... I dunno...
We will see what happens.
Much obliged for your help.
PB