I thought this might help/assist others who might be in a similar position so thought I'd post the information I gathered during my experience.
I was looking to purchase some boots for work but I also wanted to be able to use them outside of work as well so I wanted something that could be worn in a casual setting as well as for slightly more formal occasions.
First brand that came to mind for me was R.M. Williams for obvious reasons and while they are pricey (least for me when they aren't on special) I understand the $500-$700 you spend on them is money well spent. On top of that if you're willing to do the small amount of maintenance required on them you'll likely end up with a pair of boots that will last a lifetime BUT I'm lazy and rough on my possessions so I was looking for something a little more expendable while still being at least a little durable but more importantly, cheaper.
So I decided to look up a bunch of brands to see what they had on offer and this is the list I came up with. There are likely thousands more but this is where I started and I ended up with something that suited my requirements.
Ariat
Baxter
Blundstone
Dr Martins
Hush Puppies
Julius Marlow
Mongrel
R.M. Williams
Redback
Redwing
Rossi
Steel Blue
Thomas Cook
Thursday Boot Company
Windsor Smith
These are the Aussie companies from above since it seems to matter to some people: Baxter, Blundstone, Mongrel, R.M. Williams, Redback, Rossi, Steel Blue, Windsor Smith.
Keep in mind though that sadly not all of these companies manufacture some or all of their products in Australia.
Next up some sites and stores to purchase the above products from.
https://www.allingtons.com.au/workwear/boots/
https://baxterfootwear.com.au/
https://www.blundstone.com.au/
https://cheapworkboots.com.au/shop/category/boots/non-safety…
https://everythingaustralian.com.au/boots-shoes.html
https://www.mongrelboots.com.au/
https://www.rmwilliams.com.au/
https://rossiboots.com.au/
https://www.rsea.com.au/work-boots
https://www.totallyworkwear.com.au/footwear
https://workscene.com.au/footwear/boots/
https://www.workwearhub.com.au/collections/work-boots-shoes
Not all of the brands are available at the listed stores but the majority will be.
Hopefully the above gives people a decent starting point to find the pair of boots that suits their needs.
I know if I'd had it when I started it would have saved me a bit of time searching.
As for what I got, I ended up with some Blundstone boots. The #663 ( https://www.blundstone.com.au/men-s-or-women-s-style-663 ) and #659 ( https://www.blundstone.com.au/men-s-or-women-s-style-659 ) models in particular. They're the same style just one in black and one in brown so that I can swap depending on what else I'm wearing and it cost me under $300 shipped for the two. While it's a shame they're not a good year welt design so that I could get the soles replaced in future, they are "full grain premium leather" unlike a lot of the Blundstone range which list their material as "premium leather" so hopefully they last me a few years at least. After the week and a half I've had them, I've been happy with how they look and feel.
This is helpful, thanks!