I couldn't read and not reply.
I want to echo what all the wonderful ladies have said thus far. I am pleased that you will be flying back to the UK so you can have the support of your family and friends at this time. Also wanted to reiterate not naming this guy on any documents. He doesn't deserve to be involved in any way.
Regardless of what you decide to do long term I think you are being very brave and will make the right decision for you and your baby. I am sorry you have had such a bad experience but hope that you will return to Australia one day.
Best wishes and take care of yourself! x