Carl6703 wrote:
Do you have any suggestions where I could place a Wanted ad
in the UK or Europe? Thanks for any help.

One of the better places is the German glider forum. The ads are he
http://www.segelflug.de/classifieds/
Click on "Biete Doppelsitzer" (double seaters offers)

I see two ASK21 ads. Quite a few Jani are offered, too. While the Janus
is a flapped glider, it performs better than the ASK and isn't difficult
to master. (But it does spin.) I wouldn't hesitate to use it for
advanced student training.