When searching for "Season 4" on the Internet Archive, users are looking for the 1986 Revival Series , not a "lost" 1979 season.
: A common community belief is that most original master tapes for Season 4 were destroyed in a studio fire, leaving only a few episodes in existence. Survivor Episodes : Episode 4, "Fifty Years On," mind your language season 4 internet archive work
If you are looking to verify the content you find, the 1986 season typically includes: Files for mind-your-language-s-01-e-02-an-inspector-calls When searching for "Season 4" on the Internet