how to I remove rear door lock?

[Hofmiester]

I tried this at the weekend as I have an intermittant rear door lock problem, it works some of the time but not all of the time and when the motor for un/locking actuates, you can hear a squeeking sound.

I want to remove it to take a look but got stuck when trying top remove the window glass, its held in with a white plastic clip that I have no clue how to remove. The fronts have bolts but the rears dont (from what I could see)

Cheers

Ron