Since this thread has returned from the dead, I should just mention that the set recorded by Siwsann George quoted many months ago is Ed Pickford's adaptation (1972) with a few small changes and a bit left out, not traditional Welsh. I don't think that Dick Gaughan had any writing input, though I'm up for correction on that; I've heard him sing it it live, but quite a long time ago. So far as I remember, he credited it to Ed.

The tune in the DT is pretty much the one I've always heard it sung to, though it's usually given a bit more melodic variation over here (c.f. the set in A.L. Lloyd's Come All Ye Bold Miners, 1978 edn.). It may be that the person you spoke to had changed it even more without realising what they'd done, or maybe it's sung differently where they live. They might have been fibbing, of course; I'm afraid people do, sometimes.