@noble Sorry I didn't mean to be rude to you but I suppose it narked me a bit because it was an ongoing issue throughout my years in teaching that teachers of other subjects which were linear, or facts- based, didn't appreciate the slow drip, drip, way that English is learned over many years.
I think the issue is that the series was highly edited. We saw Jack and the others struggling, then trying to make good, but I expect the effort v mucking about was 70:30.
For someone like Jack who is dyslexic, they can forget a huge amount if they stop learning (ie over the summer holidays etc) as dyslexic is an issue with memory. It's feasible that he could go backwards if he wasn't engaging in learning for most of the 6 months.
At the end of the prog, he did say he wished he'd climbed the mountain at the start, to give him confidence, not 3 weeks before the end of his stay there, Which implied he had wasted the majority of his time there.
I think it as actually very brave of the school to do this 'experiment' because it was clear they'd be accused of failing the boys if they failed their exams.
FWIW I taught a dyslexic (17) and got him through his IGSCE with a C grade, after he'd failed GCSE twice, with a D. It is actually slightly easier imo.