Got the bellows and fitted the lens with a mount, some pictures I took this evening - reduced in size due to photobucket. Even with maximum extension magnification is less than 1:1, but results are better than with a zoom and extension tube (hardly surprising) and with the subject MUCH further from the lens for a given magnification.
All are at f8; With the first three I was operating the shutter by hand, having forgotten what I once knew about bellows photography in the decade or so since I last did any:
Extended about half way
Fully extended
For the last two I finally remembered to get the remote control, and I think the results are a little better.
I need to try again at f16 and f22, which will give better depth of field. My initial feeling is that it's as good as any other fairly basic prime lens - I'd probably do better with a better lens, but my prime lenses at present are a fisheye, a 35mm which isn't suitable for manual bellows, and 500mm - not the best for macro work.