Every company seems to have a diffrent set of countries they will not cover - i did a fair amount of searching before coming over and finally went for direct line - they cover Turkey but not Serbia, and they only cover for 3 months. They do cover fully comp at an extra (extreme) cost, but obviously the price depend on the vehicle as well as the drivers details, i took a Transit van which was cheap to insure in UK but more expensive for foreign travel than my car would have been.