I think you'll find that the McPeakes recorded it in about 1956, if not earlier. Old Francie McPeake is usually credited with re-creating it from a garbled Ulster version of Scot Robert Tannahill's original Braes of Balquidder. In more recent years his family have stated that he made the whole thing himself, but families have a habit of making such claims on behalf of their dear departed ones. I expect Sandy Paton learned it when in the UK in the late 50s, when it was first massively popular. Sandy Paton is sometimes credited with teaching Jeannie Robertson the tune she sang for Lord Lovel.