1. There is nothing in the rules for Bolsover that says the soloist has to play a brass instrument - we even checked with the organisers about this, just to be sure.
... there are several other arrangements for accordion and brass band...
...(and) a room full (well, half-full) of people was entertained.
So, no rules were broken, no copyright laws were infringed, and no animals were harmed... oh, and a room full (well, half-full) of people was entertained.
Any harm done... really??