@Peter ********
Where abouts in Australia do you live.
You can either use the Thai Consulate in Sydney or Thai Embassy in Canberra?
you do your application on line and it’s approved you send them your passport and paperwork as requested you post it all in a overnight express post and include a self addressed overnight express post envelope with your paperwork.
It only takes a couple of days and you will have it back.
The Embassy will send you an email letting you know it has mailed your passport back to you.