mary DS's predictions were broadly accurate, except for English, where unfortunately the actual results were lower than the school continuously predicted.
Geography ended up higher - school predicted 8 at first, then 7, then 6, then 8, and he got a 9. I think the reason was the school had absolutely no idea where the grade boundaries would be.
Not knowing what the ballpark for the grade boundaries (except English and maths) made predicting grades for the June 2018 exams a bit of a stab in the dark. Going forward, it should be a lot easier for teachers to predict with some accuracy.
As to revision aids... I think between us we have tried and tested them all, and there were some clear favourites. Tell us which subjects you need suggestions for and I think you'll get some good suggestions.