Thanks for the response.
@Jon Yes it is the "Bokina". I know what you mean hard to pitch. I watched a Canon one for months just sitting there at £465 buy it now. Thought he was being unrealistic so wanted realistic prices, hence this post.
@Algernon I've read that review/history before, very interesting. Sold one for £639, nice!! He says the one for sale is converted to K mount, the one I have is actually a K mount, got it in a camera bag with receipt and instruction manual. Notice cheaper price with no extender, £485, lol.

Sorry that'll be Tokina 90mm f2.5 AT-X macro not f2.8. Can't seem to edit post.

I happened across a mint Tokina 90mm f2.8 macro lens (Pentax K mount) with original 1:1 extender some time ago now. Obviously this is a fabulous lens but I don't get much time for macro work and my eyes aren't up to much in the manual focus territory so I'm considering selling but have no idea on a price for this cult classic. Any ideas would be gratefully received, thanks.