Emily Smith 
Joe v. the Fairies [EPUB ebook] 

"There’s no such things as fairies!"Joe is sure he’s right, but his sisters are obsessed by them. They’ve turned the climbing frame into a fairy bower, there are fairy cakes for tea and no one wants to do his assault course any more. Then a new neighbour arrives, who loves climbing trees and messing about in the pond — and has some other very useful talents too.