Culhwch
Lost Boy
As a British comedy, the film must pretend to an intelligent premise.
Just like Monty Python and the Holy Grail and Shaun of the Dead...
You're right, though, there is a fundamental difference in the American and British (and Australian) sense of humour. It's interesting that Brits and Australians are much more likely to 'get' and enjoy American humour than vice-versa, though. Probably a sympton of overexposure to American culture.