Why 'Mucky Duck Micro', I hear you ask?
Well, for starters, it's a micro! And it's hidden adjacent to the pub that used to bear the nickname 'The Mucky Duck'.
The Black Swan, as it stands now, was up until Autumn 2006 a very small, run down 'biker's pub', popular with the locals. It did, however, have a claim to fame - the interior was used in the 1981 movie 'An American Werewolf in London'. See American Werewolf in London Locations for an idea of the interior then. And it has also been used in at least one episode of Inspector Morse.
You're looking for a camouflaged film canister at ground level. Stealth may well be necessary!