ISBNs for the various editions:

9781471163777:-Cancelled Simon & Schuster UK. According to Brian James Freeman at CD via a source, 6,500 of these were released. Several online bookstore searches state no results found.
9781471163807:-The number for the e-Book listed on the CP of the cancelled UK. Several online bookstore searches state on results found.
9781534401235:-Simon & Schuster US
9781534401242:-Simon & Schuster US e-Book
9781444939880:-Waterstones/Hachette Children's Group UK
9781444939873:-Hodder Children's Books UK/ASIN:B01N5DMP9E (e-Book)