Last year also, the Korat Immigration wanted to see something from the UK about my pension. I gave them a copy of my tax receipt (P60) and that satisfied them.
Thanks Tod, on top of your game as always. Last year I had two transactions into Bangkok bank that Transferwise had put in via Kasikorm. I had no problem getting letters from Kasikorm to verify that the transactions were international. Cost me 200 baht if memory serves. Delivered while I waited. Not sure whether I have any this year as yet (I also forget to update my passbook every 5 minutes).
In Korat, the bank want 10 days to get a 12 month Statement - we must be further out or somesuch.