“It’s difficult playing at your house. You’re trying to get in the mood to slay a vampire, and then someone’s boyfriend comes in to get a snack.” It’s a problem we’ve all had. Or at least, those of us who are among the growing number of British Dungeons and Dragons players who are swapping sunbeds in Lanzarote for a cottage in the Lake District , and trading their piña colada for a couple of D4s and an orc costume. Driven by “cosy crime” hits such as The Traitors and Agatha Christie adaptations,