GUEST.CJB wrote: More details - also it appears to be a book for children, so likely to be in a school library.

This would explain the book that Tommy W. saw, but it doesn't solve the mystery of the song -- in particular, the tune, and Colquhoun's part in it. Were the poem just a poem from the 1950s or 1960s, we wouldn't be having this discussion. :-) If "Wellerman" is an actual song known to Frank Woods in 1969/1970 (note the conditional), then we have to explain where he got it.

One possibility would be that the Reed book is a republication of an older book, or uses an older book, say from the 1920s. One might wildly speculate that a teacher found "Wellerman" in this 1920s book, decided it would be a good teaching tool, and set a melody to it. It happened enough in the United States. Had it happened in America, the tune would likely have been "Yankee Doodle." But New Zealand would use different tunes. Still, this would explain both the existence of a tune and its relative rarity.

Note that I do not advance this theory seriously. It still doesn't explain the similarity of the tune to "The Lightning Tree." We really need to find the source book, whatever it is, and see what its source was.

Either that, or call up the ghost of Colquhoun and find a truth serum that works on ghosts. :-)