Just wanted to confirm that this worked for me. I used a fairly fine file instead of sandpaper, didn't have to take much off at all before it snapped in nicely (the board of the contact pad is still not flush with the edge of the circuitboard, so I could take off more if necessary).

Thanks again for the pointer. I think my keys are starting to loosen up a bit too

I still need to take a bit off one corner of the carbon backplate so it fits in the case of the keyboard part. Can anyone confirm whether I'll have to re-apply glue if I take the back off, or is it the kind of glue that will remain tacky?