No point starting with a new board at full retail price. Check the second-hand market. Some SUP riders buy boards too small for them and sell it to buy a bigger one. Some teenagers outgrow there SUPs. So there are quite a few out there. One place to buy boards in Australia is Seabreeze.com.au
Here is a link to the site and a search of NSW with the boards listed from short to long.
To find more info on these boards go to the brand's website.
Here are some of them:
Let us know if you know of other makers that make suitable boards.