The £5 was to reserve your copy of the game, it was said there was no guarantee to beta/early access and at the time there wasn't any info on the early access, just that there would be some.
I think the way they are staggering the logins is a great idea. It lets the servers fill up over time instead of 1 million+ people getting on at the same time. Just be glad they didn't charge you the full price when you pre-ordered only to find you have trouble getting in the first day.