In reply to Laura-lou:
Relax and enjoy!
Have a "repair kit": gaffer tape, cable ties, 4mtrs paracord for bootlaces etc.
Nav, Nav, Nav, don't be pressured into giving an instant position if asked, take your time and relocate before giving a definative answer, you will be asked many times "where are we now, to the nearest meter?" this can happen at any point during your assesment, be prepared.
Stay positive, look keen, look like you are enjoying yourself. You are unlikley to get any confermation of your performance till the end of the assesment, have a crack, bit of laughter at mealtimes etc, show you are comfortable with your environment and the tasks you are being set.
Cheers Adam