Steve, if you scan up the thread to 18 Feb 2009, you will see what Mickey has to say on the subject, but I will copy and paste the relevant part of his post anyway.

"I totally agree with your comment that a lot of singers don't get to grips with the treacherous musical trapdoor that lies in wait for the unwary, but I honestly feel that the original version has a musical tension that later versions lack"

The problem here is that if you have never heard Mickey singing the original composition, you can have no idea how banal and anticlimactic the Niamh Parsons version is in comparison.

I have no idea why she changed the notes in that line, and changed them so radically. She recorded the song within a few weeks of Mickey's recording it, but alas, it is her interpretation, and not Mickey's original, which has been picked up and regurgitated ad infinitum in folk clubs up and down the country ever since. It is of course, much, much easier for a relatively unskilled singer to sing the Niamh Parsons version than it is to sing the McConnell original.

Mickey said it best himself in the post from which I quoted above ..."the original version has a musical tension that later versions lack"