There’s no shortage of action in London this summer, but one of the highlights of the season has been the Pina Bausch retrospective at Sadler’s Wells, a collection of ten of the globe-spanning choreographer’s works, each created after living in a different international city as part of a roving, swirling travelogue of sorts. The run met with an ecstatic response, one appropriate for a towering talent of her stature, and yet the glory of the performances was darkened by the thought that, after Bausch’s death in 2009, her Tanztheater Wuppertal company is headed for a definite, if yet-unscheduled, demise of its own.