That's a very interesting collection of toys you've got for sale there, Paul!
That lens scope converter is a truly unique gadget in the Nikon line-up. I bought one of those in the early 90s out of curiosity and really loved it, it worked brilliantly with the 180mm f/2.8 and 300mm f/4 lenses. Very useful, very high quality and indeed quite rare these days. It's essentially an erect prism and 10mm eyepiece on a Nikon F mount. If anyone is interested,
this site has some more info and pics.
I wish you luck with your sale!
Cheers
Steffen.