Never have the words “sent from my iPhone” been so chilling. Baby Reindeer is an adaptation of Richard Gadd’s acclaimed one-man play, which hammered out the horrifying story of his experience of being stalked by a middle-aged woman named Martha, who he meets at the pub where he works. She gets hold of his email address, and starts to message him, incessantly, sometimes coherently, sometimes not, all through the night, every night. The…