Ah, so it was Ewan McColl who rejigged the song, not me - that makes more sense. Thanks, Jimmy. Any links to recordings of that version? As I said, the only ones I could find were the less poignant, less powerful versions:

Oh my father is old and my mother's quite feeble
To leave their own country it grieves their hearts sore
Oh the tears in great drops down their cheeks they are rolling
To think they must die upon a foreign shore

which in fact makes little sense. It is the singer who is going to a foreign shore, not his aged parents. Ewan, as ever, got it right.

A.