Alan Garner and the Friendly Re-write

I found something incredible last night whilst reading British Goblins by Wirt Sikes.  I have previously said how impressed with Alan Garner's writing I am, how much I would like to be able to write like him. I used the example of a story in this book:

A good Book

This is the story I was so impressed with in Alan Garner's Folk Tales:

'Edward Frank and the Friendly Cow

As Edward Frank was coming home one night, he heard something walking towards him, but at first could see nothing.  Suddenly his way was barred by a tall, dismal object which stood in the path before him.
It was a marvellous-thin man, whose head was so high that Edward nearly fell over backwards in his efforts to gaze at it.  His knees knocked together, and his heart sank.  With great difficulty he gasped forth: "In the name of God, what is here?  Turn out of my way, or I will strike thee!"
The giant then disappeared, and the frightened Edward, seeing a cow not far off, went towards her to lean on her, which the cow stood still and permitted him to do.'

This is the version I read last night in Wirt Sikes:

'Such was the apparition which met Edward Frank.  As he was coming home one night he heard something walking towards him, but at first could see nothing.  Suddenly his way was barred by a tall dismal object which stood in the path before him.  It was the ghost of a marvellous thin man, whose head was so high above the observer's line of vision that he nearly fell over backward in his efforts to gaze at it.  His knees knocked together and his heart sank.  With great difficulty he gasped forth, "In the name of God, what is here?  Turn out of my way or I will strike thee!"
The giant ghost then disappeared, and the frightened Edward, seeing a cow not far off, went towards her to lean on her, which the cow stood still and permitted him to do.'

The differences are quite minimal.  Do they count as re-writing?  In re-telling this as a folk-tale Alan Garner has removed the word "ghost", which is debatable, and removed the wording "above the observer's line of vision", which does sound very intrusive.  Mainly he has re-written the story to be a straight narrative about Edward Frank, rather than the reporting of a folk tale told about Edward Frank.

Do these changes account for the effect I was so previously impressed with, of Alan Garner telling one thing, whilst telling you another.  Was this his achievement, or the achievement of the original native Welsh person who told the tale to the folk-lore collector Wirt Sikes?

Was Alan Garner's achievement the selection of this tale, and the placing of it in a frame, with space around it, and calling it Art, which allowed me to think so highly of it?  If I had first read this whilst reading Wirt Sikes, would I have been as impressed?  I don't think I would have, although I would have enjoyed it.  I think it was the separating of the tale from it's wordy anthology home, and placing it in it's own frame which allowed me to appreciate it.  I am not knocking Alan Garner's re-telling of this tale at all, I was just shocked to find how little of it he wrote.  I thought only he could have written that brilliant bit about the cow!  But we have an anonymous interviewee of Wirt Sikes to thank for it. 

Thank you!  I love the story whoever wrote it!