Always advisable to do the eye test first as this seems to be the biggest failure factor, followed by the audiometry.
There is only a 1 in 200 chance that you have a colour vision problem so don't lose any sleep there and it's a good idea to give your ears a good degunging beforehand. I've always thought I had very clean fins but I used drops for three days prior to the test and was amazed at the difference it made.
If you've got time to kill, pop up the canteen for lunch (from 12.00) - very good and very reasonable - although you can get a brew or soft drinks all morning.
As for the run around the car park, that's been replaced as of today with a 12 mile forced march carrying full battle order kit and two jerrycans filled with cement.
HTH
2close