Look into the boot. Behind the rear lights you will see a removable panel. Remove the panel and you will see two plastic nuts they could be either white or black undo them ( only hand tight )and you will find the light cluster will come away from the vehicle you will have to do this if you want to replace the bulbs aswell. to replace just do the opposite. If the car is the new shape zafira I think the removal is the same.
hope this helps
Andy, February 2010