The thing is that the presenter doesn't actually need to know a great deal about folk music at all - that is the point. He/she needs to be the intermediary between the viewer and the subject - asking the questions on behalf of the public.

When Time Team first started, who would have dreamed that it would have gone on for the ten years or more it has done. Tony Robinson was 'Baldrick' to most of the viewing public, but he asked simple, often obvious questions, in a way that made the subject interesting, accessible and exciting. Now I'm not suggesting Tony for this show but someone who could do the same job.