In recent weeks especially with regard to high value Hi-Fi equipment I have seen many items that have been listed as "Post to UK only" receive last minute bids from outside the UK. At best this can mean the hassle of packing and posting items to far away places, at worst having to relist and in my experience relisted items NEVER sell for the original bid price so you lose money due to the "doubt" factor creeping in to bidders minds.
The answer is simple, when listing items for sale in your own country first select your "will post to" catagory then go to my preferences and block bids from those countries you do not sell to. An advantage to this is that items do not appear in simple searches from other countries. There are of course ways around this but it will stop 99% of the problems.
Hope this helps someone.
Some of you may not be aware that you can also block bids from individual bidders as well. If for instance a bidder from outside your selling area bids on an item early you can contact them to explain that you do not sell to that country (please be polite) remove the bid, then go to bidder requirements in preferences and add that bidder ID to the block bidders list. Please remember to remove the ID if you subsequently sell an item worldwide.