This has just arrived. Sarah's previous book The Riddle of the Poisoned Monk is our bestselling kid's book, and deservedly so. I couldn't put it down. A great story, fast paced, funny, educational (in a good way), gory, magical and suitable for children from 8 to 80.
Like a regular non bookshop person, I've patiently waited for the paperback to come out before reading it (I don't like hardback fiction, I think in most cases it's not necessary to publish hardback fiction), and so we've already sold one!