I think what everyone is missing here is difficulties in license applications. The amount off money you have to pay for licenses and the hoops you have to jump is ridiculous since the rules changed. This happened back when opening hours were extended.
So what venues do now is get a license that is all encompassing, to cover all eventualities.
The Jerk Cook off was a couple of years ago, personally I had a great day out, but unfortunately a small minority spoiled it for local residents. Has there been anything similar since? Horniman are saying they will do 3 events a year on the large scale, that is once every 4 months. I mean come on, is that going to be that inconvenient, or horrific?
We live in zone 3 of one of the big cities of the world, you are 15 mins from the centre of that city, we have it pretty good, so a few really busy days in a year is not the end of the world.