Hi Stewart75,
The Biblical flood story, in spite of what we were told to the contrary, is based on the Epic of Gilgamesh and not the other way round. It was "global" in as much as that was the entire world to those people in those days.
My problem with anything connected with God directing man to do something is to ask WHY? God being all powerful wouldn't need man to do anything. God could just click his fingers and whatever he thinks would be accomplished. To have man build the Biblical ark is, one could say, a test of man's loyalty, but that wasn't the case at all. The Hebrews needed people to look up to as rallying points for their faith. Trace the story back and you'll end up in Iraq - and with Gilgamesh, King of Uruk!
You'll never get a theological answer regarding Australian animals re the Ark because no such Ark existed. I say this, not because I can prove it didn't exist, no one can, but because common sense dictates that the Biblical flood story is a myth. I suggest you read books such as The Bible Unearthed by Israel Finkelstein and Neil Asher Silberman, and Ancient Iraq by Georges Roux.
Once I left Watchtower I started to read as much as I could on ancient Bible history. I was amazed at what I found. So much information is out there - information Watchtower doesn't want any of its members to find out about! One such piece of information is the flood story.
Welcome to the forum. Keep on asking questions. How else does one learn?
Best wishes,
Ian