Can we have another free allowance please Sir?

One of the options is that people can choose to pay by is direct debit. Other large utility firms such as gas and electricity providers have quite wisely (in their own interests as well of their customers it must be said) offer an inducement to their customers by way of a discount on their bills if they opt to pay by direct debit.
Plainly, if bills are discharges on the 'button' when due, then those companies are saving a fortune each year by not having to pursue late payers for monies due.