G-BBAE: all i want is NO DELAY, CANCELLATION or Overbooking!!!!!!!!!!
Trying to break this to you gently: Every passenger wants the same. And every airline wants the same (if you substitute "overselling" for "overbooking").
If you want to improve your chances, your best bet will be to charter an aircraft - although even then nothing is guaranteed.
If you can't do that, the advice that you've been given is very sound.