I don't post outside the UK. It's hard enough making sure parcels reach their destination in the UK, I'm just not prepared to take the risk. I state UK bidders only on my listings too.
Ia lso never bid on items outside the UK, because you never know when you're going to get hit with import tax. A friend of mine bought a jacket for £50 which he thought was a fair price, but then had to pay another £50 to actually bring it into the UK, making it NOT a fair price at all.
I've posted abroad for years and haven't had any problems. I always send international signed for, which probably puts a few people off these days as its quite expensive. Which I suppose could be a good thing. I have a few people every year try to get a cheaper rate of P&P before they've bid and ask for it not to be trackable but I stick to my guns, then both of you are covered in case of a loss. A few years ago I used to sell loads abroad to the USA but I rarely do these days with Royal Mail price increases. I only really send clothing items. Wouldn't bother with bulky heavy things as its too expensive and too much bother.