Have a look at the order details, if you're signed up to the global shipping it will have a uk distribution address, just send it there and they do the rest. The person in Cyprus will have paid extra but you won't have seen that. If not you'll either have to ask for the postage or cancel. Or pay it and chalk it up to experience!
Posting to a different address than the one on the PayPal account means you won't be protected by PayPal if it turns out to be fraud. I'd check with eBay but I think that will be a valid reason to cancel the transaction without losing any money.
I know this doesn't help now, but you can stop this kind of thing from happening again in the future if you look at your seller preferences, there's an option to block buyers in countries you don't ship to.