re: Murray's nationality - Well, you did ask who he was - I was just trying to be helpful, GSS!
I think you're being a little hard on him - he's a radio presenter who has gone to the trouble of putting the programme together with the help of acknowledged experts, as well as having another expert in the field, Mr Moore, on hand to discuss the propositions.
It would be delightful if all presenters were experts in every field, but that's not going to happen. I assume that he never met MacColl - I'm sure he would have mentioned it if he had - but surely he's entitled to his opinion based on the research he has done and knowledge he has? We mightn't agree with it, but so what? But we, I think, are the better for him having made the effort.