Demon Defenders: Classroom Demons by Jake Lancing
Puffin Books ISBN 9780141324586
There's trouble brewing down on Earth - and they've landed right in it. Alex, Spit, House, Inchy and Cherry - who just happen to be angels - have been sent down to Earth for spraying Archangel Gabriel with bright red ink (noooo sense of humour!) and they must stay there until they learn how to stay out of trouble. But with some odd smells and rumblings going on in their classroom, their chances don't look good.