Changing postage costs

[MummyPenguin2]

I've sold an item on eBay and I'm sure I listed it as posting to UK only. The winner hasn't paid and after a reminder message says they actually live in Europe, so can I revise the cost of postage. How do I alter this once the item has been won?

You can't alter it. You sold it at the postage price stated. Therefore you honour that. You could always send them a message explaining your mistake and tell them you need to cancel it. I was going to say to message them as well asking for more postage payment in a separate PayPal transaction from them, due to the mistake etc but they would probably say no and would think you was cheeky.
I would cancel the sale. How much would you be out of pocket?

But if you cancel bear in mind you risk receiving negative feedback from them if they aren't understanding of the reason. Also you need to update your selling preferences in settings. You can block countries to sell to. I find anything to do with settings easier to do on the actual eBay website not the app.

Thanks for your reply Ima. That's really helpful

That's fine! Anything to help. Once an auction has been won tho you can't change anything. You can change anything about the listing 12 hours + before it ends. You can do this by pressing revise item. But 12 hours or less left on the auction you aren't able to change a thing.
There is a section to 'send invoice' once an auction has been won tho. Again you find this tab on the actual eBay website, next to the item that has been won, on the drop down menu. This lets you send the buyer any updated postal charges etc but I can never figure out how to use that. But try looking into it and see. I'm no expert on that.

Tell them that unfortunately you only send items to the UK and so you will be cancelling the transaction.

When you cancel the transaction choose as a reason that there's a problem with their address.

Surely you could just send her an invoice with the revised postage.

Then send the item via eBay's Global Shipping Programme
sellercentre.ebay.co.uk/private/global-shipping-programme

Have they won the item through the Global Shipping Program? You'll still only be out of pocket for the usual local postage cost, Ebay take care of the rest.