It’s pot luck as to what you scenario you have working out your grades
If a teacher/department don’t have a range of data/evidence on a pupil after practically two years of teaching them, then that is appalling.
If you look more closely at the guidance (there are multiple documents giving more in depth guidance), it is very clear to outline what evidence teachers can use (explicitly not just mocks and NEAs) in order to make it much more fair. In all honesty, if a student has not ever produced anything (give it homework, classwork, tests, mocks, projects) of higher grade work in two years, then it is highly unlikely they would have pulled it out of the bag in the June exams anyway.
For those pupils who can pull it out the bag with very short crammed revision (a tiny minority) then that is what the Autumn exams are for.
I fully appreciate that this is a very stressful time for you and your daughter but these grades are not just going to be picked in just a couple of seconds/out of thin air)
Give the schools and exam boards a little more time to collate this guidance so that they do everything they can, not to misinterpret anything and not disadvantage anyone.