I can see the use of the personality questionnaires, especially for the face to face interview process, but I don't think it should be a reason to boot someone off. As an earlier post said, some of the questions were such fine lines, and I often thought do I want to give the obvious answer, thinking that NATS would then grill me if I looked too "perfect". In my opinion, if you have the intelligence, as shown in the aptitude test, then I think that at least warrants a ten minute interview to give you a chance to prove your motivation for the job.
Basically I think a five minute interview will tell NATS more about a person than them filling in some form for 40 minutes which they could easily make up the answers for. I spent a bit of money last week, travelling up to London, a hotel the night before, it would have been nice to have had an interview in order to give myself a real shot at the role. I'm not bitter....honest!