I called Toeff World (aka Ducati Mittelland) this afternoon, and they don't sell rearsets for the 851 any more - they thought they "ought to take them off the web site"!
They did give me someone else to contact though (the company that actually made them in the first place) so I've e-mailed them. I'll let you know if they have any.
andrew, these are the sets i've finished now, can't upload any pics again, so have u2u them to you mate. 2 extra sets available. if someone can upload the pics , they can be seen by other interested bods.