This product is used to amend an existing order such as an upgrade from a previous purchase or a postage surcharge is applicable to your order.
Once you get to checkout, there is a white box where you can add additional information. Please enter your previous order number in there so we can track payment.
It is very unlikely that you will have been asked to purchase just one i.e. £1 extra, if this is for a postage surcharge. Please add the required amount to your cart that adds up to the surcharge we emailed or called you about e.g. £7 surcharge requires you to add seven to your cart.