Quote their own terms and conditions at them, via email.
"If you are returning an item because of an error on our part or, in accordance with our returns policy, because it is damaged or defective, we will refund the delivery charges incurred in sending the item to you and pay your costs of returning it to us (either via a personalised pre-paid return label, or by refunding your return postage costs). Specific rules apply to the return of large electrical items. We will also refund the cost of giftwrapping and other services provided to you in connection with your purchase, where applicable."
no subject
"If you are returning an item because of an error on our part or, in accordance with our returns policy, because it is damaged or defective, we will refund the delivery charges incurred in sending the item to you and pay your costs of returning it to us (either via a personalised pre-paid return label, or by refunding your return postage costs). Specific rules apply to the return of large electrical items. We will also refund the cost of giftwrapping and other services provided to you in connection with your purchase, where applicable."
http://www.amazon.co.uk/gp/help/customer/display.html?nodeId=1161018