Roy,
There are just two tracks by him on a double CD that came out in 2004 from the National Museum of Australia. It was called "Sharing the Harvest" and was a compendium of Australian traditional singers recorded by John Meredith.
On CD2 Duke sings "Goorianawa" and "The Great Northern Line" alias (Cruise of the Bigler/ Dogger Bank/ Knickerbocker Line).
I know when I bought my copy I was surprised at how cheaply the Museum was selling them.
Trust you are in good form.
Regards,
John