It's been a fraught start to negotiations between the European Union and the United Kingdom as talks on their post-Brexit trade deal kicked off this week.Deep-rooted differences over fishing rights have again emerged as a potential major sticking point - with a British government minister, George Eustice, already hinting that the Navy could be used to protect "British waters" against EU fishing vessels. Even a long-standing dispute over the Elgin Marbles, artefacts taken by the British from Greece's Parthenon some 200 years ago, seems to be hovering on the edges of discussions.