Skruffel,
on your pictures I only see the fuse-box at the left knee. In my (LHD 2016) car, the AVAS-box is behind this fuse box, a little more right. Not at the left knee, but near the toes of your left foot. You can only see the silver box, when you put your head on the carpet and look up.
I cut the violet wire (pin 1) on the connector C-241, and connected two wires to a real switch right beside the AVAS-off-button.
(unfortunately I have no fotos)
Works fine. Now, this switch is normally off, and I can start driving without pressing any buttons but "Power".
If you can not find the box with this information, maybe the 2016 info is not valid for your car?
Good luck
Paul