By Martyn Herman LONDON, March 6 (Reuters) - Back together again, British duo Bradley Wiggins and Mark Cavendish proved the long wait had been worthwhile as they reunited in a blaze of glory to win Madison gold at the world track championships on Sunday. Despite accumulating points in the early sprints, they still trailed world champions France, Switzerland and Colombia by a lap after 168 laps when Wiggins launched a blistering attack that Cavendish continued, with a little help from Spain. Legs pumping, eyes bulging the British duo clawed the lap back and when Cavendish made contact with the pack ear-splitting roars rocked the velodrome. More...