Hope you enjoyed that, and well done ramblingfancy, who more or less got the right answer - Return of the Native is the odd one out, for reasons which will become clear when you see the books' opening lines...
'Whan that Aprille with his shoures soote' - The Canterbury Tales
'A Saturday afternoon in November[...]' - The Return of the Native
'April is the cruellest month' - The Waste Land
'It was a bright cold day in April, and the clocks were striking thirteen' - Ninety Eighty-Four
Thanks for all your ingenious guesses!