I think Martin Carthy has been at least Lloyd's equal in tinkering and recreating, but so far as I know has never tried to claim folk authenticity for his work.

Neither have I heard of Martin Carthy trying to pass of his reconstructions as anything other than what they were.
Peter Bellamy was another song tinkerer. When he sang Fair Annie he used to state openly that he changed the story a bit because he didn't like the way it went. His adapted version was taken up by Maggie Boyle, who, to my mind, made a much better job of singing it.