Another vote for Michael Turner's: lovely tune, and very singable if you choose the right key: only an octave range.
Margaret's would be a bit tricky to sing when it comes to all those leaps in the second part - unless you leave them out and only sing the top note each time! Range well over an octave too, so more demanding to sing.
(Skye Boat Song and My Bonnie are not English, btw!)