I believe that under a strict license, long-barreled shotguns and older, “grandfathered” rifles can be legally owned and stored in the home. Whenever I’ve been involved with threads here discussing firearms in the UK, some of our British Freeper Friends usually jump in to set us Yanks right ;-) Perhaps our friends Manc or Agere Contra know the legality of the matter more precisely? I’m just going from memory here and if none of our British Friends answer in this thread I would imagine that the answer can be had with a few minutes’ web searching.