They've been spending March relaxing in the Caribbean hotspot.  And on Friday, Sir Paul McCartney, 79, (left) and wife Nancy Shevell, 62, (right) cooled off from the sunshine as they frolicked in the sea during a beach day in St Barts.  Protecting his fair skin from the strong sunshine, Sir Paul wore a long sleeve T-shirt as he headed for a swim (inset), while Nancy put on a leggy display in black thigh-skimming shorts.