Don't worry about the medical - although a lot of us do!! It'll only take that long because you'll be kept hanging around between examinations probably. The actual thing, all added together, could probably be done in half an hour or so. You'll get an ECG... eye-test (something like the one at Boots), hearing test (play extremely low volume tones in each ear).. and a physical check with a quack - listen to your heart, poke you around a bit, take your blood pressure, look in your ears, etc. That's about it, I think!
Good luck... may see you at LATCC some time.