The discussion tab on Wiki is always very interesting when looking at controvertial issues:
So it's the then chairman of this terrible group which is now making these accusations. It seems his hand written piece of paper is the only evidence there is.
BTW, here's a much better scan of the alleged membership list:
http://conservativehome.blogs.com/photos/uncategorized/2009/02/06/cuca_msp_list_amended.jpg
So I hit google and all the newspaper stories go back to this one person - a Tory MP - making an accusation against Nick Clegg based on this piece of paper:
http://conservativehome.blogs.com/centreright/2008/04/nick-cleggs-tor.html
I'm not saying he is lying, as I have no evidence to back up such a claim, but I'm not necessarily going to trust the ex-Chairman of CUCA either.