HI All, I plan to apply for a retirement extention ,on my O visa when I return next month.I would like to do the combi method ,money in Thai bank ,and earnings . I get £13000 a month ,450 pension ,and 850 ,from rent on my house in the UK. Do they count money from rental income?,also where do I go to get proof of this ,UK embassy in BKK ,or from the UK .thanks in advance.

You will get the income letter from the embassy. Info here: https://www.gov.uk/government/publications/how-to-obtain-a-pensionincome-letter-for-thai-immigration They will accept all types of income proof.

I assume the 13,000 number shroud be 1300. Using today's exchange rate that is more than 65k baht (67,782).

oops sorry it was £1300 a month ,thanks for thee reply