Split lives up to its title in dividing my opinion right down the middle. I’m not sure whether it’s a load of gratuitous, pseudo psychology nonsense or an entertaining exploitation thriller/horror. Thankfully, writer/director M. Night Shyamalan (The Sixth Sense) has managed to break out of his disappointing – sometimes awful – run of films since the mid-2000s, by pulling an inspired performance out of James McAvoy (X-Men: First Class) and creating an intriguingly sinister story with a surprising bite in its finale. It may be generic at its core, containing a few too many plot holes, but Split is clearly…