Okay,
I know Wikipedia should only be used for initial research, and sources then checked, But...
According to This Page 'Transportation' of criminals was First to America, and then to Australia (from 1788), and Van Dieman's Land (from 1803).

While I agree that We should not fall into the error of assuming that the songs are necessarily geographically or historically accurate it would be a worse error to start with the supposition that they are inaccurate.

Unless there is some reason to believe that a song which mentions VDL actually means Australia, I would take it that VDL means VDL.

Surely 'Occam's razor' applies.