"Authority over the Australian Constitution Act lies not with the Australian government nor with the Australian people, it rests solely with the UK. Only they have the authority to repeal this legislation …”
Firstly, there is no such Act called the "Australian Constitution Act". The correct name is "the Commonwealth of Australia Constitution Act 1900 (Imp)".
It is incorrect to say only the UK has the authority to repeal this legislation. The Australia Act 1986, which was passed by every state parliament in Australia, the Commonwealth parliament, and the United Kingdom, removed the power of the United Kingdom parliament to change or amend our Commonwealth Constitution, and our Commonwealth Constitution can now only be changed by referendum held in Australia.