The chairs swivel around for people to watch the film! However the audience tend to gather before the movie and loiter afterwards to ruminate about what they’ve watched, which is when the cocktail tables come into use.
Probably helps that there are plenty of film buffs in the area, what with the BFI National Archive being just up the road plus Warner Bros Studios is only a short drive away in Leavesden.
BBC - British Film Institute National Archive in Berkhamsted
I watched the 70mm print of 2001 A Space Odyssey at the Rex last year and there was reverential silence throughout the screening. Can’t recall anyone nattering during a film in any of my visits to local indie cinemas, even though most films play to packed houses; unlike the multiplexes where I always try to sit a few seats away from other groups, as invariably someone who needs to use their phone during the film