John you are right on "incidental" and I think any other interpretation is just wishful thinking.

Your Friday sessions are a different kettle of fish. Howells of course said if things were advertised or regular, then they were not "incidental". Fairly recently it became permissible to refer to Hansard to help to determine the meaning of legislature, but only if the legislature was itself unclear(!) and even then only if the ministerial utterance in Handsard was clear(!!). Whatever else is clear (or not) it is fairly clear that whatever Howells says is usually unclear.

Conversely, by the Human Rights Act (s 3(1)), it is now the law that "SO FAR AS IT IS POSSIBLE TO DO SO (my emphasis) primary legislation and secondary legislation must be read and given effect ina way which is compatible with Convention rights". I think Howells may have overlooked this so let's hope he does not read this before it is too late to slip in another amendment tonight!

Freedom of expression is not an absolute right under teh Convention. It may be subject to restrictions (etc) "that are necessary in a democratic society (case law says that this means a pressing social need must be shown) in the interests of ...public safety...the prevention of disorder or crime, [or] for ...the protection of health or morals..." Case law also says it must be proportionate.

Your session is unamplified (unless Clive turns up with his keyboard), sort of lurks in the back of the pub behind the bar and is not very visible or audible from the front of the bar.

If it hypothetically were licensable (ie not incidental) I have some difficulty seeing what pressing social need could be shown, and how making it illegal could be proportionate.

Therefore, subject always to the rule that ventilation here is not solicitor client advice and no liability is accepted (etc) I am of the view that so long as you do not advertise, even if your session is regular, it would be incidental - but these are quite special facts. It also does not mean that the Council will not take the contrary view.