Forget satnav, the best way to find your way around the wild granite uplands of Cornwall’s Bodmin Moor is to invest in an old-fashioned Ordnance Survey map. That’s exactly what writer Louis de Bernières did when he was exploring the setting for his new novel Light Over Liskeard, a “heartwarming” dystopian fantasy in which the hero (a quantum cryptographer called Q) seeks refuge and self-sufficiency in a remote moorland farmhouse while waiting for the collapse of civilisation.