Is personification and metaphor used in 'The Chocolate War'?
Actually, simile and personification are types of metaphors, as they make comparisons and analogies between things. So, if you've found a simile, you've found a type of metaphor. So, "Jerry walked to the bus like a sleepwalker" is both simile and, technically, metaphor.
Here are others:
On page 24 in my paperback edition:
"Silence fell. The school was hushed around them..."
This is personification, as it is giving human qualities and actions to inanimate objects, "silence" and "school."
On page 9:
"A strange happiness invaded him."
Here, "happiness" is personified like a ghost inhabiting a host or an army infiltrating a territory.
For metaphor, again on page 9:
"His knees were liquid and his body light as air."
Here's two similes, comparing knees to liquid and body weight to air.