Actually, I like listening to Mark but I feel that a specialist show also requires specialist expertise.
Instead of engaging a "personality" presenter with the aim of attracting more listeners to the folk programme itself, would it not be a better idea to encourage Mark and other Radio Two presenters to play more folk music on regular mainstream programmes?

"specialist expertise"
Yes, I do realise that they didn't get this with Harding either! There used to be a time though..e.g. Jim Lloyd etc.