You need to remove the trim covering the inner wing, this is done by removing the retaining clip at the front and the pas fluid resovoir cap.
The black trim then lifts off.
There is not much room to get to the back of the headlight, but it is possible.
Remove the cover on the back of the headlight.
remove the connector from the back of the bulb, by pulling it.
There is a clip holding the bulb in place, which you remove by pushing the clip to one side.
Replace the bulb, fitting it with the tab pointing upwards, refit the clip and connector. refit the covers.