Many thanks Snuffy, I hadn't seen that.
But the legal point surely still is whether a session constitutes "entertainment" or "a public performance". What is so different about a group of people sharing their love of music together for their own benefit rather than that of an "audience" than a group of people engaged in an animated and loud conversation about, let's say, football in the local pub. Isn't the distinction legally one of intent. In the case of a paid gig, there is clearly an intent to entertain a audience. In the case of a session, the intent is one of enjoying one's hobby with others of a similar mind rather than providing "entertainment" or "a performance"?
Again, probably all this has been discussed before ad infinitum and, if that's the case, my apologies.
mcmoo