.......immigration office at Chaengwattana has used 21 Day under consideration stamp for marriage and raising Thai children for quite a while now........
Never knew that. Last year, I applied in early May and was under consideration until my expiry date on 10 June 2024. (Waiting period of over 30 days)
Returned on 10 June and no bank details needed. Extension successful.
Which is more important to you, your trip to Aus or your Non O visa?
Personally, I would cancel the trip and get a new GBR passport.
I wouldn't even consider an emergency travel document.