Karl,
Its the diving you need help with, I think you have the other covered....
Firstly, RTFM. It contains all sorts of info. Secondly, LISTEN TO THE DIVE BRIEF! Plan the dive in your head. Make sure you understand it. Thirdly, remember the program is there to test your skills as a CAVE level diver. You will need to learn stuff to pass. Lastly, better divers than you have failed. Get your head on straight before the sessions. There is nothing tricky about the course, and nothing will happen that you have not been told about or had done to you before. It is just as much a mental thing as a diver thing. Concentrate on YOUR stuff, forget about everybody around you (except for your buddy of course- You need to communicate thoroughly before the dive). If the guy next to you is wearing a pink drysuit with green fins, independents and a jacket BC, this is of no concern to you. Taking the piss out of Craig for his choice in gear is not on.
Remember, you have done all this before, today is no different.
Have fun guys, good luck to the 3 of you. Godspeed.
JD
PS: One more thing. You WILL be buddied up with someone else for the stress test. Brief them THOROUGHLY! Tell them where you want them to be. Tell them you will nod your head when they can take the reg. Tell them where to hold on. Take normal deep breaths, they can hold on for 30 seconds until you finish breathing, you do not want to be the one gasping for air. Be the alpha male in the buddy team and make sure you tell them WHEN it will happen, WHAT will happen, and in WHAT ORDER it will happen. If they do as they are told, you will be fine. If not, you are the strongest diver and should get through or a second chance. An Instructor will NOT let you drown, so dont panic, just ask them for a reg if your buddy does not give it to you.