Also, having built up such a large amount of credit, don't you think you should reduce your DD payments. As has been said here, it's your money, take control of it. Every time my supplier has recalculated my monthly DD, they have tried to increase it excessively. A quick call to tell them how much I think I should pay, and they've always agreed with no arguments. You can always settle any underpayment on a one off basis, as and when required. I am with Scottish and Southern Electric, so can't speak for any other suppliers policy on DD's.