@Pip ****
i would open up your individual Thai bank account (not joint) and season as required, 400k/800k bht to obtain Thai visa and maintain as per the directive to get future extensions. Open a second, joint account and fund seperatly to satisfy the Australian requirement. Never a good idea to use a joint one for Thai visa, as you need twice as much maintained, and if the other party 'accidently' reduces your balance even 1bht below the required amount in the qualifying periods you can kiss goodbye to your next extension.