"Van Diemen's Land" is one of those "feels like a traditional song but isn't" songs. Lovely song, BTW. I occasionally sing it with an old friend of Beth's who probably doesn't actually realize that it's not a trad. song, but then her awareness of traditional Irish music is fairly lacking.
But no, I'm not aware of their having recorded anything actually traditional--although, waitaminit, didn't they record something with Maire Brennan (sorry, can't remember the proper Gaelic spelling of her surname) of Clannad? Anyone remember what that was?
Chris