I trust that people noticed that bit in the threatening letter: "I am sure you appreciate that a great majority of publicans pay licence fees and comply with licence conditions so they may provide this sort of entertainment to their customers."

The truth of course is that, as a Licensing Officer cannot help but know (which means she was in effect lying in what she wrote there), only a tiny minority of pubs have licences that permit music involving more than two performers. And after the "reform" no pub without a licence for music will be able to allow even one "performer". (The situation which already applies to coffee bars etc.)