Warren, Taff and others reading this. It's not that I disbelieve or even disagree with your assertation about the differences between the Aust and UKicon lenses (Ignore the No32's - I just threw them in as a comparison.....) It's just that both the UK and Aust telescopes are mechanically identical (?) have the same magnification, do the same job but with marginally different optical systems. JUST like some No32's. We can mix and match No32 lenses (within the bounds of optical reason of course, but not always....) so I am pressed to understand why we haven't managed it with UK and Aust Patt 18's.

For my part, I only ever see one of either sort once in a blue moon so I'm not in a position to accurately draw out the optical scematics on a pin table. But, I have a gut feeling that the interchangeability of the lens systems could be overcome. But it won't be me that works it out!