I really hope no-one objects to me adding my feelings on the matter as I am not a parent of an A level student, (My dd has sld so was never able to sit exams of course.)
I think this algorithm system of "Awarding" grades is absolutely diabolical. 
For anyone who suggests a downgraded student is whinging should be deeply ashamed. Of course every year there are numerous students who don't achieve the grades they expected but, in these cases, at least the students know it was due to their own mistakes. Distressing but you can work through and address this.
Being given a result by a computer is gut wrenching when said result is obviously a huge cock up with no obvious redress at this stage. FGS, youngsters have missed out on Oxbridge places and similar, universities where it has been their dream to study and they have worked for years to attain this. To then have it ripped away by a bloody computer and not your own mistake. Words fail me! 🤬
Can I just say my blood is still boiling for all those affected. I have just signed a petition to get this appalling situation reversed. I genuinely worry about the repercussions due to the horrendous distress caused to undeserving students. We need to put this right as a nation NOW!
My apologies for joining in when it doesn't directly concern me but I can't recall feeling so strongly about something for a long, long time.