For a good start - how about pressing the election hopefuls to replace the proposal from the Lib Dem supported but fallen Private Members Bill) with the following clearly worded exemption?

Live unamplified music.

12B (1) The provision of a performance of live music within the meaning of paragraph 2(1)(e) of this Schedule, or entertainment of a similar description, or facilities enabling persons to take part in such entertainment, is not to be regarded as the provision of regulated entertainment for the purposes of this Act provided that the music or entertainment is —

(a) unamplified.

This would at least finally free all live music that was not presenting a noise concern from conditions and restrictions applied to address this.