Where does this leave John Tams, Billy Bragg or Jim Boyes, etc?
Much of this argument comes back to Norma Waterson's observation about singers singing stuff about whose provenance they know little and which they can't be bothered to explore. Do they necessarily need to in order for a performance to be credible or touching?
            Some people evidently see "traditional" as a mood or a language rather than as a de facto pedigree.
          The answer to some of this may be in Stan Hugill's writings about shanties.