17-04-2018 12:37 PM - edited 17-04-2018 12:37 PM
The short answer here is no. If they have purchased the items and they paid both delivery costs, then the assumption is they are happy with this cost.
I have in the past combined post and refunded the difference to the buyer. I even had buyers complaining about this! It was a real hassle. Now I don't do it. If they do not ask, and they can not manage to combine the purchase on E-bay, then I just send the items as is.
on 17-04-2018 12:56 PM
Are you going to send them as one package (presumably by courier), or two? If you are going to send them in the same couriered package for less than the total postage paid by the buyer, then a part refund through paypal would be a sensible thing to do. Otherwise you should send as two packages.