DAVID HOLMES lived a young boy's dream. A competitive gymnast, he was thrust into the Hollywood spotlight having been cast as a junior stuntman on the 1998 sci-fi movie, Lost in Space.

Two years later he landed the role as stunt double to Daniel Radcliffe in the Harry Potter films where he battled dragons, explored underwater worlds and racked up more broomstick miles than anyone else in the Wizarding World. Then in 2009, David's world changed when a horrific accident fractured his C6 and C7 vertebrae, leaving him paralysed from the chest down. In a period of emotional soul-searching, he came to an important realisation: he was a survivor, not a victim.

Since then, he has raised hundreds of thousands of pounds through the David Holmes Harry Potter Cricket Cup and is an ambassador for the Wings for Life Foundation and the Royal National Orthopaedic Hospital in Stanmore. Elsewhere, David has been a published essay writer in the New York Times, and has given speeches in front of members of the royal family at both Buckingham Palace and Saint James's palace. He produced a BAFTA-nominated documentary about his life entitled The Boy Who Lived and posed for a powerful portrait in which he stripped naked and set himself on fire. He lives in Essex.

An experienced school leader and principal examiner, Michael Chiles has been teaching for over 15 years. He has delivered training both nationally and internationally, supporting teachers in their approaches to implementing effective assessment and feedback practices.

Currently an Assistant Principal, he writes blogs at GeogHod, sits on the Chartered College of Teaching Council and enjoys walking in the British countryside with his Border Collie. He is also the author of CRAFT and The Feedback Pendulum.