Where was Work Is a Four-Letter Word filmed?
1968 film directed by Peter Hall
Work Is a Four-Letter Word (1968) was filmed in Shepperton Studios and Belvedere Power Station, 2 places named in its Wikipedia article's Production section, in the United Kingdom. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Places per Wikipedia's Production section
Wikipedia’s Production section names 2 places. Each links to the sentence that says so.