You will surely have seen the posters for The Girl on the Train with Emily Blunt staring from a train window beneath the question: ‘What did she see?’ I don’t know …buddleia? Bindweed? The occasional abandoned supermarket trolley? That is all most of us see from trains and while it’s true that buddleia, bindweed and the occasional abandoned supermarket trolley would make for a very dull film, it could scarcely be any duller than this.