In longer Black Death mod Great Britian never formed and England become just regional power and rest of Europe had masive Black plague epidemic so no one colonised Aborigina (Australia).
In 1840 after researching State and Governance First Great power can take this decision to get one freee province in Aborigina.
Shortly after Aborigina will get event about arriving of Europeans and land what europeans occupy.
After that Great powers can cliam parts of Aborigina with decisions
After either Great powers partitioning Aborigina or its westernization decision about colonising inland Aborigina can be taken.
France after colonising Aborigina.