The tune in Chappell's Popular Music of the Olden Time is also pretty much the same as the Motherwell tune; apparently a tune was given in Keith's Last Leaves of Traditional Ballads, but that was with a text from Bell Robertson, who didn't sing, so I'm guessing that was the Motherwell one as well (haven't seen it, mind).  Looks like there is only one basic tune for it, and it just varies a little from singer to singer.