MacColl was talking about traditional versions of the song; recordings by revival performers such as you mention are irrelevant to any consideration of provenance. As it happens, he was wrong; the song has occasionally been found in tradition in both Ireland and the USA, though it is Scottish in origin and the great majority of traditional examples have been found there. The set Bert Lloyd recorded will have been a re-write of his own making, based on existing texts. The DT file Tamlyn seems to be a transcription of Pete Morton's adaptation of Mike Waterson's adaptation of Lloyd's adaptation, though no source is acknowledged. The matter is touched upon in the discussion Young Tamblin

MacColl's text appears to be Child's example B, from the Glenriddell MS (1791), shortened and slightly altered, and with verse 7 introduced from elsewhere. No tune is known for that version, so MacColl will have set the words to a melody from elsewhere. What did he say about the song in his sleeve notes?