If it's a "he", probably Eric Bibb...?
I'd go to see Joan Armatrading, but then I saw her already last year in a fantastic performance at Cambridge Corn Exchange. I can't imagine a half-hour set in a muddy tent is going to better that. And although some of the other acts are very good, I'm not playing the ticket game.
To be honest, it's par for the course with the Corn Exchange. They're a small provincial box office, catering for small provincial events. They may be trying hard to do this, but they simply don't have the staff, premises, skills or experience to handle a large event.