I've seen Alexander Robb's tune on Bronson,and checked it is the one used by Ewan MacColl and Mary O'Hara. I didn't mean the text sung by MacColl and O'Hara was from Alexander Robb, but I admit that when I wrote "from the singing of Alexander Robb" I was inaccurate. Thanks to everybody, especially to Bill D, Mick Pearce, Malcolm Douglas, for solving this problem. R