Is 'Straw Dogs' a British film? Well, it was filmed in Britain, with a British cast (Hoffman excepted) and a mainly British crew. It'll do for me.
The infamous rape scene tends to dominate most discussions about the film, but it's also a taut thriller imbued with an heavy atmosphere of impending doom. Peckinpah captures the claustrophobia and strangeness of small community living very well and, of course, returns to his traditional themes of honour and what it means to be a man (violence, mainly).
David Warner was uncredited as village idiot Henry Niles because he was still struggling to walk after breaking both heels and was concerned his prominent limp might cost him other work. It didn't, of course, he's been in everything.