it can not be because of an incomplete application because you can not submit it before it is completed and paid so no way the embassy would know about this
not so difficult with a proof of residence - 500 baht immi - they will want a copy of the tm30 and see your passport. Tell them it is for opening a bank account because it can be used for different things and the reason is on the proof of residence. I did that a few months ago and had no problems opening an account in Krungsri
hi Stuart - the Thai embassy in Denmark say that to get a non o (basic) you must be +50 AND retired. There are mistakes on their website - is this one of them?
I don't use them because I don't want to give my passport number to a private company I know nothing about - and besides that after immi have changed their system it is much easier to report from the official website