Do the O/S one first, it's easier!
Gives you some idea where things are, as you will be working blind on the N/S one.
Remove (as said previously) the indicator bulb AND the wiring plug on the headlight bulb. If it's a 1.6HDi (think the 2.0 is different) remove the lid off the relay/fuse box, too. Believe me, any little gains in access will help.
On the plus side, once you have done it a couple of times, you wonder what all the fuss is about...
Oh, and for some strange reason it is easier to take the plastic cover off the back of the headlight, than it is to put it back on! :brickwall:
I have tried pressing what I think I should but I am scared of breaking it. Is it the small lighter coloured part on the top at the back?
What are you trying to do - remove the blinker?
Change the front side light, near sde