Lyn Gardner: “I can only ever review what I see. I can’t review intent, and I can’t review the fact that the people putting on the show will almost certainly have expended much time and effort, and may even have mortgaged someone’s granny’s house to raise the money. So where does that leave the critic – and indeed the audience – when it comes to community or participatory theatre, where often the performance is but the tip of the iceberg?”