Hogwarts expatriate Daniel Radcliffe is the headliner here, but you might also recognise Zoe Kazan, one half of the meet-cute not-couple in Canadian-Irish production What If (retitled from The F-Word). She wrote Ruby Sparks (2009), a fun and acerbic satire of the Manic Pixie Dream Girl trope (an increasingly problematic term) in which she was the dreamt-up effervescent love interest for Paul Dano’s brooding, needy novelist. It is something of a pity, then, to see her taking on much more unchallenging genre material here. Adapted from T. J. Dawe and Michael Rinaldi’s Canadian play Toothpaste and Cigars, and directed by Michael Dowse (who did the winning The…