Just spoken to MTV. They are going to e-mail people shortly, but for those with superfan tickets, here's what I was told:
You need to go to MTV Camden between 12 and 2pm with ID to get wristbands (both of you together if there are two people). You then queue at Trafalgar Square from 3pm for priority access. They will let you in before GA (i.e. some time before 5pm) so you'll be able to get to the front.
If you're unable to get to Camden to collect wristbands you can still go straight to Trafalgar Square and use your tickets to gain entry but you won't have priority, so will enter with GA.