Can you show photos of how the mount is mounted...?
I would have to take it all apart, but all you would see is a silver (+) screw head in the back of the bezel; what I did was:
Set the TOMTOM Mount on the Bezel where I wanted it, and drilled straight through it, from the TOP of the mount as you see it, and straight through the bezel at one time.
Then, I put in a screw that fit and would grab, from the back, and screwed it in through the back of the hole int he bezel, then through the TOMTOM mount, so it pulled tight up
against the bezel. You can see the top portion of the screw there in the picture, the POINT of it, at the center of the TOMTOM mount. I even left the rubber on, so it
doesn't vibrate or chatter against the bezel.
From the back of the bezel, I marked the saw lines, removed the mount, and sawed out the corner, then put it back on.
Check my Facbook Album, you'll see my Visor mounted 7" Android Tablet, has all my tunes on it, but I changed the wiring, ran them through one of the mount holes of the Visor: