METHOD 2: Access by removing the screen (suggested by Quantum Byte)

If like me you are unable to find a gap to detach the aluminium back from the frame so instead I tried accessing by removing the screen using a sharp tool (a metal blade such as a Stanley knife or a flat-ended spudger) as in the video (not my work).

Unfortunately, this is not as easy as in the video as the entire outer edge seems to be glued. Furthermore, the screen cracks v. easily. Since my screen was already damaged, I ended up breaking up and tearing the screen off. I am perhaps not best to advise on this method.

I suggest using a hair dryer/ heat gun to melt the glue sufficiently to make the screen detach.