At the very start of all this I did Email the MU and was impressed to receive a very prompt reply from the Assistant General Secretary of the MU, themselves, no less.

It was very precise and factual and confirmed that the fact that the act requiring a PEL applied to three of more performers in pubs, whether they were paid or not.

I have not explored the question of whether a session would constitute a public entertainment, with them but it maybe a good idea to do so.