I hated 'Spies' after my first read and I had no clue on what it was about. However, after reading and analysing chapter by chapter, the novel grows more and more interesting ^_^
Opening: Motif of the 'privet', theme: memory, adulthood/childhood, POV: old Stephen (looking back on childhood, hence links the two together), and of course, the purpose of the opening is to make the readers want to read on (go on, lie shamelessly on how it provokes reader's interests...)
Mrs. Hayward: There's a ton to be said about her. Her transformation, her relationship with Keith and Stephen, her role as an adult and a woman in the novel... etc
Hope this helps and is not too late!