The personality questionnaire was part of the stage 1 testing for my last application (2 years ago). I guess with NATS' policy of no feedback at any of the stages, you wouldn't know if a failed stage 1 was due to the questionnaire or any/all of the other elements, which also included the mental arithmetic testing. I passed the questionnaire last time so if I fail it now (after being 100% honest on both occasions!), I'd be worried that my suitability for the role has deteriorated with age.