To add a new delivery address, just head on over to your address book. You'll then need to set this as the address for each four punnet snack box order you'd like to change. You can do this from your orders page. Click 'manage recurring order' or 'manage one-off order' for the order you wish to change, then choose your new address from the 'where to?' box.
Any changes to your order will need to be made before the cut-off time if you want it to affect your next delivery.
If you want all future four punnet snack boxes to be delivered to your new address, you can make this your default address from your address book.
When checking out via the graze shop, your default address will always be automatically selected for you. Be sure to change this if you want your shop order to be sent somewhere else!