It is often worth complaining about 'one off charges'. My Mother in law who is getting rather senile, did not pay enough money off the balance of her creditcard to stop it going over the limit, once they had applied their fine. I complained on her behalf and the fine was refunded. British Gas similarly tried to apply a late payment charge, which, when I challenged, was refunded. Where these type of charges are being applied for the first time, you can normally get the refunded.