@BadKitten, thanks for the suggestion, but no, DS really wouldn't engage with a tutor. He just panicked mid-exam, I think, suddenly woke up to the fact he had missed vital exam technique info in English for several years. They are going over it in class. He has the skills, he reckons, got wrong end of the stick about what they wanted.
Funny aside... parents are moaning on Facebook (parent school info page) about new rigour in uniform rules at school (same old rules, new HT efforts to enforce). I am the only parent who posted that my DC likes the crackdown. Now he doesn't feel like an Oddball for actually following the uniform code.