The 1960s atmosphere is very strong in this story of two sisters (aged around 9-11?) who go playing in the marshy, spooky area near their moorland home, known as the Battlefield, though we never find out when the battle is supposed to have taken place. The vagueness is part of the charm of the story, and though there are some very strange events, all are explicable as natural phenomena.
Mary Russon's classic Sixties illustrations add to the period flavour.
Somehow, knowledge of Mayne's reprehensible actions, for which he did time, does not prevent wholehearted enjoyment of his stories; one is able to separate them (as if they were a classic typeface by eric gill? Or perhaps "Sun Arise"...) Though I could not help seeing Freudian interpretations abound......