Jon, we apply the monthly direct debit discount on your energy account twelve months after you begin to pay by direct debit.
The date when you're due to receive a statement is aligned to the date when a meter reader will attempt to take a meter reading at your home, so this will determine when your statement is due to be sent out to you. For some customers, this means that they receive a statement just before their anniversary date, while others may receive a statement just after.
And as you comment, the discount will appear on the first statement after the anniversary date. However, you can be assured that the discount would have been applied to your energy account on the anniversary date - and this will remain the same every year that you continue to pay this way.
I'm also an npower customer and my discount is awarded in October - just before my statement is due and so I normally wait until April for my discount to show but I know it has been credited to my account.
