I'm going to move slightly away from the main thrust of this thread with a few thoughts on what this song has meant to me.
When I first started to go to folk clubs in the late 1950s, Barbara Allen was often sung and it was always the "In Scarlett town....." version and I knew why it was so well known; it was because it was reproduced several times in the BBC Singing Together booklets and radio broadcasts. I was taught it at junior school by an excellent teacher (who was to become my excellent mother-in-law ten years later). An accomplished musician, she didn't need the radio programmes but she used the booklets. I will have to say that I strongly disliked the ballad because of one line that stuck in my craw : -

... made every youth sing well-a-day

Do me a favour! I thought. However much I get into this folk song stuff, I will never sing or like this song. I started to hear different versions with a different first verse and I thought they were better but I thought that I would never learn it. I was wrong.
I knew the name of Stanley Robertson and had met his aunt Jeannie and a number of his cousins including the great Lizzie Higgins. Stanley was booked at the first TMSA festival when it moved from Blairgowrie To Kinross (1971? 1972?) and John Watt, the compere called on Stanley Robertson to sing. He came up to the front, looked around the audience, said nothing then started to sing -

It fell aboot one Martinmas time
When the green leaves were doon-falling....

I felt the skin move against the bones on my forearms - always a good sign with me. Where did the power and majesty of this singing come from? I asked myself. By the end of the first verse, I knew I would have to learn it. I spent a long time that weekend in his company and we became firm friends, us visiting him in Aberdeen and me arranging folk club bookings at our club in Lewes and in other discerning clubs.
I have heard other fine versions since then, notably Vic Legg's and Brian Peters' reconstruction of the version collected by Cecil Sharp in 1918 from the ex-slave Aunt Maria Tomes from Virginia but Stanley's compelling is still the top one for me