I used Scoot for part of my journey, the SIN-BKK leg. Plane was quite new, comfortable and cabin crew are pleasant. Beware the inflight meal and you probably need to pay more for baggage. Note for Singapore transit you must use airlines within the same family for arrival and departure. Scoot is in the Singapore Airlines / Silk Air family. Recommend.
Thanks. Yes, it is a single booking with Singapore Air for Mel-Sin-Bkk. I had a separate booking for domestic flight Per-Mel. If I cannot get to Mel, then I need to adapt to Per-Sin-Bkk.
Thank you everyone. Absolutely I will avoid risks and advise the embassy of the changes to the original internal flight. Better safe than sorry. So grateful your advice is consistent and obvious.
I obtained a TR Visa from RTE in Canberra recently, the process was fast and efficient. If you phone in to the visa extension directly, they will guide you as to what you need. I was told that I needed a return flight already purchased for the process to complete. Just in case - you can only apply for STV in Australia if you are an Aussie or minimum a permanent resident.