Just to let you all know that it seems to be sorted now - thanks to all of you for your very helpful and constructive comments. Really appreciate! (Also, just want to say publicly that the Swedish Embassy in Bangkok have been great!)
Yes, I don't know why they are so adamant that it's not possible here in Udon - they say it's because I already did one extension. (I came beginning February). Anyhow, trying again on Monday. Let's see!
Hi Risto! I fulfil the requirements for both the bank and the income. I understand what you are saying - but according to the immigration office here I have an additional stamp for an earlier extension in my passport which eliminates the possibility. Don't know why. I'm going again on Monday to try again. The Swedish embassy are being really helpful and hopefully this will get resolved.
Sorry for confusing things mentioning my earlier Non-O. I didn't ask them about an extension for visiting family - but I will certainly give it a try. Thanks for that!