Just to say that delays in October and November were mainly due to the fire restricting services and resulting in a lot of people having journeys altered and therefore having to do manual check-in. This has now changed, service is much better, and I am very sure (based on my experiences on 23rd December) that your time scales are fine.
N.B. I just realised that I always pick my tickets up a week in advance as I pass through Kings X on my way home, so my times are only based on goign straight to check-in. If you need to pick tickets up, leave more time, and don't go to the first machines you see, are there are loads which are often unused.
Vicky