As far as I have been informed it will consist of:
Technical exam
Group exercise
Interview
Sim test
The technical exam is based on "handling the big jets" I have been told from a person from easy pilot recruitment. However a person I know who has recently done the interview, told me the exam is copied from "preparing for your cathay pacific interview".
The sim test is performed raw data on a 737-300, with a SID out of Luton followed by some turns and airwork, followed by one or more full procedure approaches.
If you are not familier with the 737, generel flight profiles can be found here
http://www.fmcguide.com/media/profiles.pdf
Tips!
The 737 is sensitive in pitch, so be gentle on the controls.
The airspeed indicator on the EFIS display will show you what is happening with your speed (arrow), if your speed is about to go up, the arrow will point towards a higher speed on the speedtape and wise-versa..
Good luck!