Whilst I sympathise with the recruitment team who were faced with a deluge of applications and had to find a way of narrowing down the flood into a trickle suitable for interview, I wonder whether the customer service question was the best way of doing it.
It was the only opportunity to put forward one's personality but was fairly vague and although I thought I supplied a good answer, had I realised its importance in the process, I might have written a longer and more detailed essay. By contrast, BA's application form included 5 opportunities to put your personality into the application and those answers could reasonably give an impression of one's personaility.
Incidentally, this is not sour grapes. I hope they get the right people. I a probably not it anyway!