WITHNAIL AND I is reported by one of my favourite specialty video stores here as their Number One all-time rental - a pretty good record in a shop that has tens and tens of thousands of popular movies, art-house and foreign films.
I want to add Terry Gilliam's astounding BRAZIL (1985) to my list of top fave Brit movies of the 1980's. I have the 3-disc Criterion set, most useful for comparing the incredibly butchered USA Paramount release with the full version seen by the civilized world.
BRAZIL fans may find the comments from Buffalo, NY's Film Seminar series interesting
Buffalo Film Seminars Goldenrod Handouts Scroll down to "Fall 2005" and you'll find their PDF on BRAZIL. The Buffalo series is fascinating, so I hope you'll explore some of the other entries - including several PnP's.