I'd go along with everything said so far....be yourself, gen up on current affairs, get lashed and pitch up on day 2 bright eyed and bushy tailed (I don't seem to be able to do that any more for some reason!)
What I would say is have a clear idea of what you want to achieve... what happens if they offer you Nav or Ops support? Nav's a great job, but isn't for everyone and Ops Support can be v.challenging, but v. boring in some jobs. Don't be afraid to say no to an offer and walk away......once you're in it's a long contract to be stuck in a job you don't want.
Good Luck though......tell us how it went!