Shed of the Dead.

Trevor is 'between jobs'. He spends his days avoiding his nagging heifer of a wife by hiding out in his allotment shed and painting figurines for his wargames with his agoraphobic friend, Graham, and dreaming of his heroic alter-ego, the battle mage Casimir the Destroyer. When Mr Parsons, one of the other allotment tenants, petitions to have Trevor removed from his disgrace of a plot (he's not there to grow stuff!) an argument ensues that leaves Trevor with a corpse to hide. Unfortunately, this untimely accident coincides with the zombie apocalypse and Mr Parsons' return is just the beginnings of Trevor's problems. More pressing is whether or not he should try and save his wife and her beautiful best friend, who both he and Graham have a thing for.