Nice diagram, Andrew.
Mental models are crucial in ergonomics. The selector for the electric windows on my Espace controls Left-Null-Right. I still turn it the wrong way because my model is 10 o'clock, 12 o'clock, 2 o'clock. And theirs is 8 o'clock, 6 o'clock, 4 o'clock. The picture on it shows their view, but mental models beat instructional pictures.
Jonathan