There's an American folk song called "Every Night When the sun Goes In" that was collected by Sharp (in English Folk Songs in the Appalachian Mountains). You'll find the words (in the Digital Tradition) if you click on this link. It isn't a waltz, though.

I'm wondering if the fact that Sharp claims it as English means that there are parallel songs in the English and, potentially, Australian folk traditions. Is the theme of the song anything like what you remember from your childhood, Aussieharper?

Wish I could help.
Claire