I finally found the elusive sauna which almost everybody has heard about but never been able to find. It took some while and a great deal of walking about to find it but the best thing was that, in the process, I also discovered the gogo bar area in Hatyai. It still isn't anything like BKK or Pattaya, or even Phuket, but for all those who are thinking of a trip to the south, here is the link to my blog post.
The Rowdy Reprobate: Getting to GL Sauna and men's gogo bars in Hatyai
My apologies to everyone for posting just a link as I took photos of the way there and all my directions are on the photos to make it easier for people to find the way. There are too many pictures to upload the entire set to every forum where I post regularly, and I'm too lazy to copy and paste repeatedly.