The secret of dealing with councils is NEVER ASK PERMISSION TO DO ANYTHING! DO NOT tell them where you intend to perform. DO NOT send them an itinerary - If you do not bring something to their attention they will not know it has happened.
As far as dancing on a public space is concerned, the only people who can ask you to stop is the police, and unless you are causing an actual nuisance or obstruction to traffic, they have better things to do with their time, and anyway are probably somewhere else (especially if NOT being somewhere else would mean tangling with a Morris Team. If someone complains to you, explain what you are about (it will delay the move off), then move on with good grace - we are not here to make enemies!
Quack!
GtD