"But on the subject. I think quite a few session players (myself included) have a bit of a phobia about performance which is subsumed into the relative anonymity of a session."

It's a very good point is that. I'm an untutored harmonica player, reasonably proficient I hope, but I didn't come from much of a musical culture. I was forty before I played anything at all in public. I've played in front of an attentive audience on my own or with a single accompanist many times, but even now I can feel like a fish out of water doing that. I feel much safer surrounded by a few other melody players in a session. I've always tried to single out and listen actively to a strong player to whom I can "latch on." I actually think I play better that way than when I play on my own. Very subjective, of course. In a session I feel like I'm collaborating rather than performing. But we've never cut ourselves off from the pub customers, as I've said before. That's just not us. Incidentally, our sessions were never very big. Double figures were a rarity. I've been to big sessions elsewhere of twenty or more - not keen on that vibe.