I see there are more answers to your later question, however this one makes the problem clearer (to me anyway). I don't believe they have the right to ask for proof that you are married, and I can't see why they should. You could be brother and sister, or even unrelated to each other with the same surname (perfectly feasible if a bit unlikely!). I am sure what they want is proof that the name you are asking for the account in, is actually your name, which they must do by law. I suspect from what you say that it is not your name at all. For further information see the answers to your other question.