Might be worth checking if you ever need a One Time Passcode and co op won't do international calls.
For me Santander require a Uk phone number, which I won't have.....and I figure an international bank will be much more efficient than a building society based in europe...
Not sure if this helps but I was under the impression if you apply in your own country for a visa before you travel you need medical insurance first where as if you apply in thailand you don't.