Hey Grant,
Yes, I have finally found somewhere... well, sort of!
Here's what I know : The classes will be in Adliswil, quite near the Migros there. It's going to be 175 chf for 7 lessons and will be held midweek evenings. The teacher speaks English.. I've been assured.
Here's what I don't know : The person in charge has promised to send some info but not mailed it to me yet. This would include the exact address and what this place is called!
From our phone conversation, I've been told it'll start on 19th Aug, but that I should receive some info before then! They'll be held in smallish groups and we'll be learning the 'crawl'.
I can let you know once I receive more info soon.
Hope this helps

, will post when I find out the name of the Hallenbad.
PS: When I posted this thread, I had several PMs to 'let them know' if I found somewhere, so hopefully they're reading this too!
Cheers
W.C