For the past few years friends and I have enjoyed the house band at Baan Rim Nan. The group we favored doesn't seem to be playing there now. If anyone can help shed light via post or pm, we'd like to track the group down for one of our holiday evenings out. 

You could have a look around facebook

I'll ask Thai friends to get on it.... any key names or words would be appreciated.

Many bars have facebook pages , try to locate their FB page and then have a look around their photos and see if you can see them , put the bar or bands name into FB's search function

Thanks for the sensible recommendations.