Simon Morris accepts that, for all the hard work of everyone on a movie, most people are just looking at the actors. Three character studies this week, including Mike Leigh’s Hard Truths, based on weeks of actors’ improvisations… Black Bag, in which a spy investigates six possible traitors, including his own wife... and the last – and some say the best – of the Six Wives of Henry the Eighth, Catherine Parr in Firebrand.