Just wondering what would have really happened if the mummers had gone ahead.

The lincesee would have been prosecuted, and probably pleaded guilty. That is why it did not take place inside. As it is not really up to the mummers, the important people are only the licensee and the council

It is a good point though, in this case if the licensee were found guilty of proving an unlicensed public entertainment, What penalty (if any) apart from a conviction would he have had?

Only the Court can tell us that.

Any licensees out there willing to test it????