what you do with santander is go into one of their branches and ask. then the person on reception stares at you like you're mad while you repeat the request several times and explain to them what a swift code is. then they go and get someone else who also doesn't know the answer so between them they decide to phone someone at their head office. this person also doesn't know. you then walk out in despair, go home, and find the code at the top of your last statement
Its at the top of the statement with some banks.