DrJack54

That is correct . Siam legal have stopped assisting with opening bank account. Believe Maneerat Pattaya still possible. Not sure about thaivisacenter in bangkok

Yes

None of what you list will make one iota difference

It's a waste of time in recent years things have changed. Ignore the bring a Thai friend with account at that bank or a Thai government employee etc etc. I am stating from my own experience. I have extensions from non O based on retirement and even big branches in Sukhumvit wanted a "certificate of residence " OR letter from embassy. UK,USA,AU do not provide that for address. Also 800k in your pocket will not help. Fortunately I had success with Kasikorn, however I had a non O (not a tourist visa) Also already had an account with another bank. An agent can open an account with BBL. Cost approx 4500b

Yes important to have a renewal window at a time that suits the individual. If the preference is to have your renewal few months earlier then obtaining a new non O on return entering visa exempt not a huge deal. If that option is chosen make sure not to obtain a reentry permit.

In most offices the 90 day report due date has nothing to do with annual extension. Some offices do the report along with your extension. Not sure why they do that as the two are unrelated

OP, reports of being able to do an extension early, (eg couple of weeks) added to the normal 30 days and some offices 45 is possible. That has occurred where there has be evidence of necessary travel and some evidence such as flights etc. However that does not change your ongoing "renewal date" The only way to do that is to start over. If married to Thai you can change the date by obtaining a 60 day extension to visit wife. In addition an agents may be able to assist with earlier renewal.

OP, you can also enter visa exempt and obtain non O based on retirement and then 12 month extension. Best option for ongoing stay in Thailand. A reentry permit will enable trips back to UK. https://aseannow.com/topic/1311886-visa-exempt-to-retirement-extension-process-and-cost/

I think that is your best option .

OP, file a TM30 (change of address) Then when your next annual extension is due, do it as normal at your new immigration office.

Get a 12 month extension and multi reentry permit.

OP, my understanding is that Iranian citizens require a tourist visa for Thailand You could obtain a reentry permit to enable you to exit Thailand and reenter via land or air. Note the reentry permit can be obtained at the airport on day of departure.

There are reports of after extensive stay a chap sent his elderly mother to KL and back same day. Had very hard time at immigration on arrival back to Thailand. To your other question ....you won't have any issues there is significant gap between your trips to Thailand. I never understand the urgency to get back to Thailand. Why folks don't check out places such as Saigon for a week amazes me.

Prior to your current stay in Thailand when were in Thailand prior to that.

OP is now aware of his misunderstanding. Topic closed

Yes. Can obtain reentry permit at his immigration office and at airport day of departure

Think we can close this thread. Snide comments not productive

As my thai GF states....Money is #1. My guess is that he doesn't, otherwise he would have a non O marriage with extensions. The financial requirements for marriage is a very sweet deal

I will state it again. You do not understand the requirements. The fact you have bubbled through it looking for "bank guarantee letter" is just one error. You are referring to "bank letter". That letter simply confirms you are the owner of the account and the balance on date of issue. For proof the financial requirements have been met you provide bank statements or photocopies of bank book.

Seems some immigration offices are moving to "bank statements " for money in bank method. CW included.

It's not the bank. You do not understand the "bank letter" and other requirements. Outlined clearly by @Georgealbert and others.

The OP stated very clearly that he does not intend to return to Thailand.

Not long. Allow 30 minutes extra however waiting time most likely way less

If that site is correct he could consider entering Thailand visa exempt and apply for the Non O at his Thai immigration office.

20k baht fine. That's it. Plus ban according to length of ban