For additional charges in units of pence. Please change the quantity in the window on the right to the extra amount you have been asked to pay in your recent e-mail.
Example. If your e-mail says you need to pay an extra £0.50 (50 pence), please change the 1 currently in the window to 50 and then click in the shopping basket. On the next page, if the sub-total shows £0.50, click on the Go to Checkout button and proceed to the payment options.