In my (limited) experience, banks give a poor rate for Foreign Exchange . If you want dollar notes, the Banks or Post Office seem the only option, but check their rates carefully. If you do not need dollar notes , I suggest trying xe.com which I have used. When you open an account they will either transfer by Electronic Funds Transfer to any account abroad, or issue a bank draft that can be paid into any bank account abroad. Currency Fair also give a very reasonable rate and has the advantage that you can "bargain" on their web site with sellers of dollars. Currency Fair will only move funds by EFT.