The system was set up to be fair though, in that each school could decide how best to grade, based upon the students experience over the last year. This makes sense. Some schools had no disruption, some kids were off multiple times, others not at all. Some finished the curriculum, some only managed half. Good or bad on-line provision. Mocks or no mocks. All schools had access to papers before hand, and each was very focused in nature, meaning the DC's didn't have to cover the entire curriculum.
Grades had to be based on the "cohort". If you produced an essay, then you had to have the majority of the students do that same essay in order to grade and give evidence against the whole cohort. If over the year very few students managed to do essays, then perhaps the school couldn't use those, and therefore chose to do exams only?
Predicted grades are also always a minefield. Is it 20% over estimated? I don't think any mock grade can be reasonably used to predict a year end outcome.
I suppose at the end of the day, as Madame says, you have to trust that your school has done the best for the students, in the only manner that they could have done with all circumstances taken into consideration.