Battersea Arts Centre, LondonIn Ben Duke and Lost Dog's smart, wryly subversive and sexy dance-theatre piece, Juliet and Romeo didn't die in that tomb. Worse … they grew old togetherShakespeare's lovers sit side by side in matching armchairs, a pot plant in the space between. They're approaching middle age and their marriage has hit a rough patch; they no longer talk, and Juliet starts to reveal that Romeo "is havi…