When John Harrison lived in London, he took me under his wing, and introduced me to the singing of Paddy Tunney Joe Heaney Bert Lloyd Harry Cox and many more. He was a great fiddle player and I backed him up on guitar on one memorable (to me) occasion. I have not watched the film but will do. For me Mike Waterson is one of the best interpreters of traditional song that this country has ever produced. I learned some interesting studio recording vocal techniques from them both.