The trouble with Civil Disobedience on this , as Russ suggested, is that the law is cunning. It isn't illegal to make the music without a licence. It's illegal for the people in charge of the premises,whatever sort of premises these may be, to allow people to make the music.

So it's no use us parading around making music. Though technically it's illegal making music on a parade, so far as I know they've never tried to enforce that. So I suppose a musical pub crawl round the streets of London announcing the fact that it didn't have a Public Entertainment Licence, might be worth a shot. (It'd have to be London for any hope of media coverage. The rest of the country doesn't really exist for the national media, apart from spectacular crimes and disasters.)

What we've got here is a classic case of "repressive tolerance" - a law which, if an attempt were made to rigorously enforce it, it would be uninforceable, so they keep it in reserve and just use it when they want to; but in the meantime it dampens down people doing things without asking permission.