I didn't know that was an option. Sounds like they have taken notice of what is happening. Of the last 23 transfers I have done only 3 appeared as Thai bank transfers. I raised the problem with Transferwise some time ago.
22 of the last 25 transfers have been recorded as international transfers. They use 3 partners, Bangkok Bank, TMB and Kasikorn. The problem only arises when they don't use Bangkok Bank.
I bank with bangkok bank who are very good, my problem arouse because I use Tranferwise who have 3 partners, Bangkok Bank, TMB and Kasikorn. If the Bangkok Bank partner has not enough funds then the transfer it as a Swift payment through one of the other partners. Out of the last 22 transfers 3 have been by Swift. I get two payments each month.