Why a mixed blessing Michael? Those who want to can go and sing - those who don't can stay home.
Though Nantwich did manage to fit some audience in too - which made it a bit tricky for the soloists as the 'choir' filled the main body of the church, then orchestra and soloists, then a small audience (in what I think might be called the Transept). So which way would they face (I had difficulty hearing them when they turned to the audience).

A friend went along to what she thought was a performance and found that everyone else was singing!