Barclays/ Hsbc . I Keep two just in case . For eg. I had a online fraud , the bank blocked the card and issued a new debit card (sent to my uk address whilst I was in Thailand ), I could transfer funds to my other UK bank and use the other debit card. Also use Royal Mail redirection service if you expecting lots of letters. In. Barclays/hsbc you can Freeze /unfreeze debit card temporary from the mobile app to prevent any fraud . They have online chat features so you donโt spend a fortune calling UK if any issue arises.
Money should be enough if you stay away from bars and scammers, but being a driving instructor from UK , looking at people driving around in Thailand will drive you nuts๐