Nissan Micra 2003 Tailgate?

A few weeks ago my boot kept opening whilst driving. The locking system kept clicking and the open door symbol was displaying on the dash. I had to keep stopping the car to shut the boot. Now the boot won't open at all. The doors are still opening with the central locking. I have looked in the manual to see if there is anyway of opening my boot. It tells you to put the back seat down and slide a lever. Where is this lever, i can't find it, the drawing in the book makes no sense ? Please can anyone help. Thanks