The Brideshead Revisited features a side character, a certain Captain Foulenough. In Russian translation his last name is rendered as Буремглой, obviously referring to a Pushkin's line
Буря мглою небо кроет
(The storm covers sky with darkness)
It is a famous poem, known by every Russian fourth-grader.
The search for foul enough in a similar context yields An Island, by Edwin Arlington Robinson:
a storm foul enough
I trust the translator; I am sure she came up with such rendering for a reason. On the other hand, I doubt that Robinson was known in 1945 England as much as Pushkin in Russia.
The question is, did Waugh intentionally attach a hidden meaning, and did he expect this hidden meaning to be understood by an average reader?