I'm not sure about Science tests as I know not all providers have them, but for most Primary PGCE maths tests you don't just need to know KS3, you need to know GCSE level maths. I was told by UEL (I've applied this year) to revise GCSE maths and a little of the level just below it. I also applied last year to different places and the test I undertook was GCSE level. I've got the CGP GCSE Maths Complete Revision and Practice book and would really recommend it as it explains everything really clearly. There are constant practice questions and even exam papers so you can review your knowledge. I've found it really helpful so far. I think it's about £13 from Waterstones but I'm sure you could get it cheaper on Amazon. Good luck with it all!