How does Peter Ho Davies use imagery in Think of England?

Davies uses Sarah's shoes as an image to reflect her coming of age..... her innocence and her later loss of the same. When we first meet Sarah, her shoes are perfectly polished. When she rides atop the handlebars of Colin's bicycle, her shoes remain polished and without a mark, just like Sarah's flawless reputation. When Colin leads Sarah into the emptied pool, she scuffs her shoes and immediately thinks, "I just polished them." She is seemingly aware that the scuffed shoes just might serve as a sign that she is no longer innocent.