I understand your problem. For some reason when ever you type the word helmet in a listing it restricts the listing to uk only. This is very unfair but i dont know any way around it otger than not including the word helmet. However that restricts the amount of hits the advert gets.

Some eBay sellers restrict sales to domestic buyers (because it is generally easier and less risky) - in which case International bidders simply cannot bid.
I have been selling my duplicate UK police insignia on eBay and do allow International bidders. Should be listing some more in about a week.
I am in Arizona (USA) by the way.
Hope this helps.