NavList:

Dave Walden, thank you very much for your efforts on my behalf.  Your modification has shows me what’s possible with Excel.  This is one of four ideas I’m looking at.  Firstly, I could find a Appleyard Computer; take it to bits; and photograph the three discs from directly overhead using a proper frame.  Secondly, I could attempt to find someone to attempt to correct the elipticity of my present photograph digitally.  Thirdly, I could continue working with the Excel drawing you’ve provided me with.  Finally, I could just get on and draw the discs using old style tech drawing, which I taught for a short time before PCs made the subject redundant, but neat printing was never my strong point.  DaveP