UK based drop shipping company looking to expand to Australia

I currently operate a drop shipping website based in the UK, selling only to UK customers. We have grown nicely and our next natural market to develop into will be Australia.

I have just been looking into the steps we would need to follow to reach the Australian market and am slightly confused! First of all, I tried to buy the domain for our website with .com.au but had to sign up as a new business in Australia to do so, and the sign up form only allowed for an Australian address so that wasn’t successful. DO we need to be an australian business to operate?

I then looked at sub domains and markets in the settings of my current store but got thoroughly confused!

The other aspect to what we would like to do is that the products we offer to our Australian customers will be slightly different to our UK customers. It is likely we will have someone managing the operations/logistics in Australia (but not essential as we will have partners/suppliers who will be shipping the items for us) but ultimately it will still be owned and managed by us.

Any help or pointers in the right direction would be hugely appreciated!!