As they’ve been misused Ed visas will be a red flag to immigration and could lead to questions and hassle whenever you try to enter the country. I don’t know how long you hope to stay for? Remember you can stay for nearly 3 months on Tourist Visa.
You can extend for 30 days at any Immigration Office, it’s fairly straightforward.
You don’t need a return flight to get a Tourist Visa, an onward flight to a neighbouring country is fine. Whether they’d accept a flight to Singapore, I don’t know but the London Embassy is pretty good to deal with so it’s worth asking.
If you apply for a Tourist Visa they will want to see an onward flight (doesn’t have to be a return) out of Thailand and probably within the 60 days validity of the visa.
If you travel without a visa you are likely to be asked by the airline at check-in for proof you are leaving Thailand within 30 days. Again, doesn’t have to be a return flight just travel out of Thailand. You are unlikely to be asked for proof by Thai immigration.
you keep on repeating this assertion with zero evidence as if it’s what happens with all agents. It is extremely rare for that to be the case and certainly never the case with any of the numerous agents in Pattaya who all deal with Chonburi immigration.
Gillian Dodd A re-entry permit is easy to get at any Immigration Office, or even at the airport when you leave if you’re not going to be near an Office.
Again, you’ll need to get the timing right as regards when you want to get an Extension.
At what stage in your trip do you want to go to Brisbane?
If you time it so that you return to Thailand with 30 days or fewer left on your total trip then you can get a Tourist Visa for your first entry and then just enter Visa Exempt on your return from Brisbane. Eg 50 days in Thailand, 10 days in Brisbane, 29 days in Thailand.
You could even do that earlier (as the Visa Exempt can be extended) but might have an issue with the airline at BNE.