Photoclubalpha

This seems stupid but I am trying to replace the battery in my Sony remote hand controller. I can see the "door" but even after seemingly placing lots of pressure and getting it half way open it will still not give.
Can anyone tell me if it rotates on a hinge and how much presuure is required to get this open I dont want to smash it and make it useless.
Many thanks
Ralph

There's a small lever (or whatever it is called) just next to the "door". Push it toward the "door" itself and pull the "door".