Folks don't we think we are looking too much into this with respect to alphabetical order? Probably be in order of test scoring, wouldn't you think?
Person who comes 20th may not be able to make it now so number 49 get the next shout. Would you say thats more probable that getting the results sorting them into alphabetical order and then calling.
I also still think they will look at the application forms of those from about 30th best score downwards and may bump people who have slightly dodgy answers. It's what I'd do if I was in HR at Britannia. Plus I'd also be surprised if nobody from 49 onwards was as the second stage, but we'll never know so c'est la vie.
We should all chill out with repect to this, go and sit in a darkened room until Tuesday evening (making sure we have our mobiles with us of course)