Re changing words to make the song more comprehensible: I do that pretty routinely, but I don't actually think that "alope" is any more comprehensible than "relope." I learned this one from the Young Tradition recording, and Peter Bellamy had such a distinctive way of singing "relope" that I just can't imagine it any other way.

I do, however, sing "The secrets of *my* heart, dear girl, and the best of *my* good will / So let *my* body be where it might" in another Copper Family song, "Adieu Sweet Lovely Nancy." I think the Coppers sing (or at least most people who learned it from them sing) "your" for the first two and "my" for the middle one, which to me doesn't make any sense at all.