Hi
There are arrows on one side of the key pointing to the metal part, hold the key pointing to you with the arrows underneath push the other side away from you (which is on top). You may need a small blade or screw driver to start it off, be carfull not to damage the key or yourself.
once you have put the new batteries in go inside the car and press the central locking for 5 secs, the doors wil lock and and unlock. Then point the key fob at the receiver in the car (press the button ??). the car doors should lock and unlock.
JOB DONE !
Andrew J Hughes, December 2009