Danny Boyle's follow-up to his Olympics triumph is a frantic art-heist thriller that falls well short of Hitchcockian subtletyWhat do you do for an encore once you've captured the nation's heart and blown its mind with a stunning Olympic opening ceremony? How do you follow dropping the Queen from a helicopter?The answer, for that uniquely talented director Danny Boyle, is to change tack with a high-concept psychological heist thriller, headspinning in its ambition.