PJ unfortunately I only met that couple once, they were just traveling around and found out about our session.
I just did a quick search with www.alltheweb.com (I stumbled on this a couple months ago thanks to mudcat and now I only use this search engine)
and came up with a couple sites one is www.kora.harp.net which advertises some celtic harp workshop in switz. but if you email the instructors they might let you know about any sessions.
also http://perso.club-internet.fr/d140557/IRL.html I havent figured out those blue clicky things yet. but this site lists sessions in belgium, switzerland and france. Also the comhaltas site or ceolas I cant remember has a list of sessions around the world although not necessarily up to date as sessions come and go and not all are listed. Cheers Petr.