Yes you will do some more tests but revision is not really going to help you it's at the you either know it or you don't stage. They really only run them to check your BARB score was not some sort of fluke and to confirm you have the academic ability for what you are hoping to join. Selection centre is more about fitness and suitability to service life, I wouldn't worry about the tests. Good luck.
Well the maths test is no more than quite basic GSCE grade. I do know a guy who failed it at his first attempt, but he bought a GSCE revision book and retook it and passed with a very high score. If you're that worried, root out one of your old school books.