I agree that one can't be too censorious of Lloyd. However, no matter how the song came to him, it is inconceivable to me that he actually thought it was a traditional song; he was too well-read and too careful a scholar to check the Anderson book and not realize he was reading original poetry. So he was pulling the wool over people's eyes. But at the same time, he did it in what one would have to call a good-natured, and well-intentioned, way. That is, he wanted publicity for "industrial folklore" to show that working people in industrial jobs had cultures just as worthwhile as the peasantry. And I rather suspect that he enjoyed the private joke of rewriting traditional songs and re-introducing them to singers without making his interventions clear.
Malcolm, it was the Gregson articles I intended to check when I got home, but I seem to have misplaced the folder for the moment. Did he mention whether any of the Anderson songs survived into the 1950s in oral tradition? Greg mentions a late 60s date, but of course by then the revival was in full swing, so the farmer could have learnt it from Paul and Linda Adams!