Forget tikka masala – chicken katsu is the new true British national dishIt's not particularly authentic, nor is it even what the Japanese call katsu - but Britons have gone wild for itKatsu Curry from ‘The Japanese Larder’ by Luiz Hara, £26 White Lion Publishing It is nearly 20 years since the late Robin Cook, then foreign secretary, declared chicken tikka masala to be a “true British national di