Bloomsbury additionally released an adult edition with a different cover design to the original, in paperback on 10 July 2004 and in hardcover on October 2004. A hardcover special edition, featuring a green border and signature, was released on 8 July 1999. In May 2004, Bloomsbury released a Celebratory Edition, with a blue and purple border. On 1 November 2010, they released the 10th anniversary Signature edition illustrated by Clare Mellinsky and in July 2013 a new adult cover illustrated by Andrew Davidson, both these editions were designed by Webb & Webb Design Limited.