Above Datums, would be the same Flt Lt with the annoying 'good to go' catchphrase (sounds a bit like Badger from the kids TV show Bodger and Badger for those who remember it
).
A nav will invariably get you lost and not own up to it.
Don't have a bet about how much you can eat when you get back, most painful twenty quid I ever won!
Enjoy, at least it's still summer!