I grew up in Australia and we sang those Australian carols every year at school, so I grew up with them ingrained on my memory. The first time I ever saw the 'Three Drovers' and 'Out on the plains' I was six and learning to play recorder, and my teacher gave me a bunch of what you'd call 'carols of the world' to learn :) Thanks for helping to keep them alive!

BTW, some of these carols (and others) are performed on the CD 'The Australian Christmas Album' released in 1998 and I'm pretty sure still available. I bought it to get them... :) It has the following songs:
Christmas where the gum trees grow
The three Drovers
Six white boomers
Carol of the birds
Boomerang of flowers
Christmas in the scrub
Off we go the Bethlehem
Mary and Joseph's lullaby
The Five days of christmas
Merry christmas (sun gleams bright)
and then 5 'traditional' christmas songs to round out the album.