Thanks kindly for that. So the idea would be to pop into the bank before heading to the Immigration office. Can you get hold of the bank letter and statement at the same time?
For an extension of stay based on retirement, the monthly income method, you will need a minimum income of 65,000 baht a month for every month of the year. You will require a 12-month statement of your account. With Bangkok bank, there is a minimum wait of 5 working days to obtain this statement that is ordered from Bangkok. The cost is 200 baht. The letter, on the other hand (100 baht), can be written while you wait. Prior to obtaining the letter, you must withdraw 100 baht from your account and then update your bankbook. This is to ensure that the balance on the bank book is the same as the balance on the letter. Finally, the balance on the letter will be in £ Sterling converted at the daily rate of exchange to Thail baht. Strange but true.
Of interest, if you have a Bualuang Online Internet account, you can download a statement for the past 6 months. The facility does not go beyond 6 months. A 12-month statement can be obtained by downloading 2 x 6-month statements, one for the 6-month period halfway through the year and the other at the 12-month point. I have done this and it was acceptable to Immigration.