Sorry to hear that Vic154. I could be wrong but in terms of the aptitude tests I dont think the pass mark is particularly high. I took and passed my stage 1 a couple of months ago but I remember thinking that I must have failed as I only managed to get through about half of the questions on each of the three sections. If you are confident in the accuracy of the 30ish questions that you answered for each section then you probably did enough to pass.
I know you can get booted out on the basis of your answers given on the online personality test that they set between the 1st and 2nd stage, so I imagine that they could also boot you out based on your answers from the stage 1 personality test. The idea that they can dismiss you this way without actually meeting you is crazy in my opinion but unfortunately this seems to be the case. I think they are probably testing your honesty more than anything else though so if you want my opinion for next time, answer the questions quickly with your gut instinct. As soon as you start pondering an answer, you start thinking about what you think they want to hear and thats when you start answering inconsistently and get caught out.
Good luck for next time!!