As an unaccompanied singer I find it very odd how so very many of the comments here are mostly about tunings and tablature! And how many speak of "playing" the song - I always think more of SINGING a song.
Forgive me, I don't want to sound at all like I'm doing a put-down here - but why on earth would anyone want to play the accompaniment to this song as Paul Brady played it?
Surely you'd rather want to find a key that suits YOUR voice, and to select your own choice of chords to harmonise in a new way, to forget about his vocal phrasing altogether & take the words and use them to re-tell the story in YOUR own way? I mean, he's recorded a truly wonderful presentation of the song - copying what he does is always going to be less effective than what you're copying, so why try? I really don't get it.
But let me agree that Paul Brady's performance of it is just superb - and I mean that predominantly in terms of the way he SINGS the song, which is just utterly staggering. I imagine he could have sung it with the same impact (on me at least) without guitar accompaniment at all. Many people forget that old songs like this would almost NEVER have been sung with instrumental accompaniment until the folk revival.