This is what the preamble says:
reamble)
An Act to constitute the Commonwealth of Australia. [9th July 1900]
(The
Commonwealth of Australia Constitution Act 1900 is an Act of the Parliament of the United Kingdom at Westminster)
Whereas the people of New South Wales, Victoria, South Australia, Queensland, and Tasmania, humbly relying on the blessing of Almighty God, have agreed to unite in one indissoluble Federal Commonwealth under the Crown of the United Kingdom of Great Britain and Ireland, and under the Constitution hereby established:
Seems pretty clear the Commonwealth of Australia exists as 'an Act of the Parliament of the United Kingdom at Westminster' and 'under the Crown of the United Kingdom of Great Britain and Ireland.'
If the Queen becomes separately the Queen of Britain and Ireland, and the Queen of Scotland, and the Queen of Australia, but is no longer the Queen of the United Kingdom (because the kingdom is no longer united), what happens?
At first I thought this was just a joke, but the more I read the less crazy it sounds.