Well, the Coolscan V was waiting for me when I got back from Le Mans last weekend.
The scanner and the SA-21 unit looked pretty clean, but there were dents in casing.
I knew the unit had been in storage, and only tested as far as turning on and getting the green light - but it was cheap, so I was happy to take a chance.
Stripped it down, the dents in the case hadn't caused any obvious damage to the internals, motor drives were working fine.
So I cleaned the mirror (which was pretty clean) and stripped/cleaned the SA-21 - tested it out on an XP laptop with NikonScan, and it works a treat!!
Not had chance to compare it directly to my V500, but the scans at first glance were comparable to some I had had done at a Lab.
Just got to have a play with both Vuescan and NikonScan on my Win10 PC to see which I prefer. I had read that if you install Vuescan (demo) first, then you can use NikonScan on Windows 10 as long as you don't re-install the Nikon drivers.