Can't remember hearing him ever singing it in public - but I was staying with them while I was rewiring their lighting system and they sang it together while driving home from The Singers Club in the car.
The story of him composing it over the phone was the one I understood to be true; Peggy was in America at the time and needed a song of a certain length - he obliged with FTE.
I was given a tape by Peggy of as many of the commercial recordings of it she was aware of, which included: herself, Mary Travers, Harry Belafonte, Johnny Mathis, Vickie Carter; Roberta Flack; Andy Williams; Kitty White; The Smothers Brothers; The Kingston Trio and Elvis Presley - (no Ewan).
Can't remember which one he once described as sounding like somebody on ground level serenading his intended on the top floor of a tower block (might have been Presley).
Jim Carroll