Also, You do not, and cannot, use a 30 day residence cert for any proof to give to the ATO (because virtually anyone can get one). You just need to prove, in Australia, that you qualify as a NON resident of Australia. Which is a whole different thing. A registered overseas address is good to put on your next tax return, but a good Accountant is much more important.
On arrival to Thailand, you need to register your address with Pattaya Immigration within 24 to 36 hours, in soi 5 Jomtien. To do that you need your rental agreement, copies of your passport and pages, fill out the form. Once you get the TM30 receipt, you apply for a residence cert which costs 300 baht. You can use the resident cert to get a licence (with a medical cert), buy a vehicle and open a bank account. It is valid for 30 days. If you intend to be a NON resident of Australia for tax purposes, you should visit a good accountant and get them to notify the ATO on your behalf that you will be leaving Oz and a non resident. You must also be paid from outside of Australia and it is recommended to be into a foreign account. It also helps to rent out any property in Oz, not have any bills in your name, and even sell vehicles if you want to legit.