Stuart MacGregor wrote another novel which seemed to capture what the '60s folk-scene in Edinburgh must have been like - "The Myrtle and Ivy" has a central character who is a medical student and singer trying to make his mark on the folk world. I must have picked the book up round about the time he died, and puzzled for a long time who the author might be, assuming that somebody connected enough to portray the folk scene in so much detail would still be active in some way. A couple of years after, John Barrow (of the Edinburgh folk agency Stoneyport) sang "A Sandy Bell's Man" on a visit to Dave Walter's Lytham Folk Club. I quizzed him afterwards about the song, which I remembered from the book, and he told me of Stuart MacGregor's death. He also mentioned that there was another novel, but I have not been able to track that down. Perhaps "The Sinner" is the one he was talking about?
I just found a copy on Amazon - several copies out there if anyone's interested!