Licencing authorities are comprised of elected councillors and their paid officers. If most of the people in a pub want to start singing, and they all choose to sing the same song, plenty of councillors will let that go, especially if they are going to stand for re-election. This is not rocket science.

Officers will tell councillors, and they will meekly accept, that the law does not permit them to turn a blind eye or to 'let it go' a regular (and /or advertised) occurence such as these. And using the definition of the word 'performer' as anyone singing in a pub, this will be entirely correct, in South Yorkshire and Derbyshire as it is everywhere else in England and Wales.

Snip - The law doesn't come into it, either now or (I expect)in the future.

Does this area already have a devolved Government? One that enables them to make their own legislation then?

If this councils in this region can openly and leglly enable these fine events in pubs without PELs, it is rather important that they share the knowledge of how this is done, to all the other councils who claim they cannot enable equally fine events without PELs.