Reviewed by GREG KING Director: Joe Cornish Stars: Louis Ashbourne Serkis, Dean Chaumoo, Tom Taylor, Rhianna Davies, Angus Imrie, Rebecca Ferguson, Patrick Stewart, Denise Gough, Noma Dumezweni. The mythology of King Arthur has provided the spark for many films, ranging from the musical Camelot through to the animated Disney film The Sword In The Stone to John Boorman’s Excalibur through to (shudder) Guy …