The Royal Mail Special Delivery guarantee assures a time by which the delivery will arrive on the next business day after despatch. This means in the vast majority of cases, your delivery will arrive on the estimated delivery date by the guaranteed time on your selected delivery option.
The only notable exception to this is when orders are despatched on a Friday with an estimated delivery date of Monday (or Tuesday if Monday is a public holiday in the delivery country). Royal Mail will occasionally choose to deliver an item marked for standard next business day delivery on a Saturday - even when we have not ordered Saturday delivery.
Occasionally the local delivery office will choose to attempt re-delivery on the next business day, however they may also leave a "Something for you" re-delivery card which will give you three options - collect from the local delivery centre, collect from a Post Office, or request re-delivery. Please see https://www.royalmail.com/personal/receiving-mail/redelivery/for more information.
Please note that if you chose re-delivery, you will not be able to change the delivery address and you need to provide 2 working days notice. Please ensure you collect your order or arrange re-delivery within 18 days of the original delivery attempt, or Royal Mail will return the order to us.
Unfortunately Royal Mail class early delivery as being delivered before their guarantee, so no refunds are possible when this happens. We'll show a warning on any dates when this might happen, so you are aware of the possibility before choosing that delivery day.