How do you Change a coil pack on a Scenic 2?

For the 3rd time this year, I need to repace a coil in my unreliable Scenic 2. I resent sending back to the garage to have it done and pay 80 quid for the privelege. I want to change it myself. I know it wont be hard to do as long as I know where to look and what to do, so I open this question to pro mechanics or good DIYers who can advise me of what to do

Ian
November 2009