To put the unsuspecting kiosk owner's mind to rest with regard to his personal safety, I've had iPhones for three years now and have never had any problems even though one of my chargers isn't even an official Apple one (Belkin). There was a spate of exploding iPhones a while ago but I've never heard of a British charger going bang unlike the US version according to a Google search I did on reading DaveR's original post.