Hey guys, I just did my stage 3 and 4 on the 6th and 7th June, and I'm going to be off to New Zealand with CP53 in September!
In terms of the stage three, the posts on page 26 by PAJ and the summary by "Borat" linked at the start are excellent in terms of helping you prepare for both the group exercises and the interview. Remember that Google and Wikipedia are your friends here, especially with Wikipedia linking all sorts of interesting information in relation to the partner airlines and current industry events. If you're interested enough to read around the subjects a bit then this will come across well. Always remember that CTC want you to pass and do well, so try and relax and don't worry about being asked trick questions.
The only advice for stage four is just to listen to your instructor and try to relax. The instructors there are excellent and explain everything really well, so even if you've never sat at the controls of an aircraft before they'll be able to look after you. If you do make a mistake, such as loosing height in a turn, this is okay as long as you identify it and say that you've identified it - it shows that you've been listening and know what's going on, and if you can take corrective action even better. It is difficult to handle it if you've little experience (I only have 8.5 hours in a Cessna 152), and I completely messed the landing up, but I was able to discuss what went wrong with the instructor afterwards and show that even though I messed up I knew what I did wrong and what to do next time. All in all great fun and an amazing experience.
Good luck to all of you who have stages coming up, and I hope to see you out in NZ, especially the guys who I met over the last few days who helped make the stage three and four fun!
Andy
PS. If there's anyone else out there on CP53, say hi!