The Carthy/Simon issue wasn't about the song, as you ought to know, Jim; but about the distinctive guitar accompaniment, which Simon copied note-for-note, including the (in those days, unusual) phrasing; and about the implied claim that Simon had written the whole song himself. That's all sorted out now, though, and there's no need to rake over the ashes; though it is an object lesson in the perils of making assumptions about the nature and status of what we may think is traditional; and the extent to which it can be considered to be "up for grabs".