We’ve all read the article. It does the rounds with the dispiriting regularity of an unwanted dish on a sushi train. Classical concerts are dying and if they are to survive they need to evolve, to innovate, to banish (variously) seating, silence, dress codes (for musicians), dress codes (for audience), programme notes, formal venues… But among so much institutional hand-wringing and professional self-loathing I’d like to take a moment to celebrate one classical tribe getting innovation exactly right: period music groups.