A thought struck me during my bangers and mash...

I assumed this "It was 'The big session' and yes, it was the only session" was from the OP (though now I look it doesn't actually say so). But if it was, then the many suggestions above that he should have just gone to look for another session don't really apply. In an ideal world, if you're 'running' the only session in town, then you'll have been warned that it will probably attract a mixed crowd, so you can proceed accordingly. But perhaps these guys were not warned. Another lesson for the organisers, perhaps, if this is where the problem lay. (Does anyone know them well enough to point them at this thread? If I was them, I'd want to know about it). Tom