So DS's offer is 3 As. He is confident that he will get A or A star in 2.
For the third, he's worried.
He got a B in the mock (not enough revision and an unlucky selection of essay topics).
Last year's cohort in this subject did not do brilliantly - a new syllabus which was still bedding in. 2 years above did do well, though.
He is in a very high achieving class - when they are ordered, he won't be towards the top.
So, since the teachers are not allowed to tell the students the grades they're entering, I guess he will need to carry on revising all the way through the summer to be ready for a potential exam in September.