This Australian edition of the Adventurous Four, as with most of the Oz editions, is clearly identified by the plain spine and Angus & Robertson text.

The UK editions all have a picture that continues around the spine and frequently on to the rear of the book.

From what I can see the artwork is not original, and appears most likely to have been re-drawn by a local artist on behalf of Angus & Robertson for the local print run.

The two samples below make this most apparent. The one on the left is the UK Edition while the right hand side displays the Australian publication.

Obvious differences are in the spine and the overall colouring. However it is the lack of finer line detail in the tree and the childrens clothing that makes it apparent that it has been redrawn.

The form of the children and the dwarves (at least, I assume they are dwarves) appear 'flatter' in the Australian issue.