Willie o' Winsbury - I've heard two tunes to for this song (Dick Gaughan does one and Martin Simpson does another) - and I love both tunes. There's one in the database at Willieclickie and it might be the one Simpson does, but it sounds a lot different to me.

And there's a ballad tune I can't recall any name for, but I have Ewan McColl singing it in my head, and I think there's a Lord Arnold and a Lady Margaret in there somewhere, but I could be wrong - maybe if I hum a few bars? It's not pretty - it's powerful. (Aarrgh - maybe it'll come to me.) Sorry.