I don't have much wisdom with the aptitude tests, I only did mine once, but don't overlook the interview!
Have they given you feedback for the interview? It's very good to know, especially if you're having another crack, but if you failed, it will be absolutely vital that you know. You don't want to make the same mistakes twice, as all it will do is cost you time and a lot of money, so definitely ask for some feedback! The interviews have definitely caused me a few problems.