I actually changed the headlight and sidelight bulbs in my 307 a few days ago. Its quite easy really. Look at the area under the bonnet where the headlamp is located and you will find 2 circular covers. Twist the inner one ( this is the one for headlights and sidelights and the outer is for indicatiors ) anti-clockwise so that it comes off giving you access to the lamp connections. Next, pull the power supply of the exsisting bulb and then unclip the metal spring holding the bulb in place. Once unclipped replace the bulb then re-attach the metal spring then finally connect the power feed back up and hey presto your done! Make sure that the circular cover is replaced properly and tighted other wise it will fall off somewhere as mine did!!!!