I suppose I'd also ask a few key questions about what you might have done differently:
1. Would you have allowed the procedure to downgrade students by more than one classification?
2. Would you have ensured that, if there was even the small chance that a student at a given centre would get a U grade, one student *must* be awarded that grade, regardless of their teachers' assessment?
3. Would you have decided not to apply the algorithm to small classes?
4. What is the minimum threshold for predictive accuracy, by attempting to match to the 2019 data, that you would have regarded as a successful test? Ofqual's data suggests, for example, that it was able to "predict" accurately only 26.7% of all grades awarded in Italian A Level (the worst performance for their model), and had an absolute upper limit of 67.9%, for History. In raw terms, this means that the model was shown to get 15,000 grades out of 47,000 wrong. Assuming that this was the best possible result -- exam results are also, after all, driven by random chance as well as a student's skill -- then is this an acceptable amount of misgrading? If not, how would you propose to fix this?
5. Is it reasonable to adjust the teacher's predicted grades, but to treat the way they ranked students as "perfect"? As far as I can tell, in the Ofqual approach, if the teacher's ranking put one student ahead of another, that was preserved in the final prediction, with no attempt to account for the possibility that the "better" student may have had an off day. Would you have tried to correct for this, and if so, how?
All of these are questions you should really have tried to ask already, and really boil down to a well-known problem called the ecological fallacy (or perhaps a fallacy of division): what we can say about the student population as a whole means more or less nothing for any individual. The class of 2020 may well have appreciated that, taken collectively, their grades needed to be smoothed out to be compatible with previous years, but individually this led to injustice after injustice. There is simply no resolution for this problem -- or, at least, not by any algorithmic process.
None of this is to dispute that, taking the centre-assessed grades literally, this is the highest-achieving year ever by a phenomenal margin, but it's a mistake to assume that teachers were being deliberately optimistic, or were basing their predictions on nothing; at the very least, it is difficult for anybody to judge *which* predictions were optimistic, and by how much, with any degree of certainty for the individual. Put another way, the fatal flaw of any algorithm, designed by Ofqual or anybody else, is that it is treating exam results as deterministic when they are manifestly not.