Reviewed by GREG KING Director: Benedict Andrews Stars: Ben Mendelsohn, Rooney Mara, Riz Ahmed, Ruby Stokes, Tara Fitzgerald. Based upon the controversial Olivier-award winning play Blackbird written by Scottish playwright David Harrower, Una is a confronting film that deals with some difficult and troubling and taboo material. Fifteen years ago, a 13-year-old Una (played by newcomer Ruby Stokes) had a crush on her next-door neighbour Ray (played by Ben Mendelsohn, from Animal Kingdom, etc), a much older man. She ran away with him, and he was eventually …