There are more theatre openings in London this week than decent sunny spells, many of them featuring some familiar (read: off telly) faces... Under the Blue Sky, a story of three intertwined love stories with Catherine Tate, a couple of girls you'll recognise from Cranford, and him from the IT Crowd starts previews at the Duke of York today. Over at the Vaudeville, more Cranfordians tread the boards in The Female of the Species......