Faztaz,
If you have been asked to do a Personality questionaire, then you have made the minimum grade for the initial tests - Well Done! But beware, coz you can fail the PQ!
I had my stage 3 last week and we took the opportunity to ask HR about it. It seems to be that if you pass the initial tests by a wide margin, then its pretty much impossible to fail the PQ. However, if you only just make the grade, then it is quite easy to fail the PQ. As at this stage you don't know how you did, then you can't know how easy it is to fail on an individual level. Savvy?
Hope this helps,
BW