The Igniter (black box in the photo) twists to the left then pulls off, then the bulb is held in place by two spring type clips.
You push down each clip and move it away from the bulb. Looking from the back of the unit, the left clip pushes down and slides to the left then pulls back, the right clip pushes down slides to the right then also pulls back and out, then the bulb sits there until you pull it out.
Just realised this thread is a few days old now, might as well post anyway it might help anyone in future.