@steve
Hi,
Regarding your first question, yes you can allow payments in customer currency by choosing the option Customer Currency for Paypal under currency restrictions.
Refer:
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And regarding payments being converted to AUD before payment, yes it is possible to make changes in the flow of the module to get the amount converted to any currency. If you are comfortable with programming you may make the changes yourself or may ask us to do it for you. If you want us to do it for you raise a ticekt at https://webkul.uvdesk.com/en/customer/create-ticket/.