There used to be something almost apologetic or at least self-deprecating about British road movies, as if the makers were well aware how poky and circumscribed they risked looking compared with the thousand-mile journeys essayed in American films. But in this new British road movie, a tale of two troubled teenage boys driving from London to Scotland over a couple of days, it’s as if the film thinks its every cliche is as newly minted and revelatory as the latest dashboard software update. There’s a singing-in-the-car moment of bonding, an accidental discovery of a beautiful seaside landscape, and even that old chestnut, a backstory reveal involving the ashes of a dead loved one. The only thing missing is a high-speed escape from a traffic cop, but maybe the ubiquity of speed cameras on British roads means that doesn’t happen much any more.