Swan theatre, Stratford-upon-AvonBrad Birch's drama aims to explain how it felt to be the centre of the world's attention in the war but being narrated at becomes tiring When the RSC invited Brad Birch to write a play about Britain, his first impulse was to travel 8,000 miles, to the Falkland Islands. His uncle had served in the conflict over the colony and, 40 years on, Birch wondered about the islanders' experience…