I was stuck for 90 minutes on Wigton station looking for some Physics. I went back to the polarised sky idea. The Sun was to my left shoulder and diagonally up at about 45 degrees from me. I think my shades allow vertically polarised light through, so the polarisation direction is perpendicular to that 45 degree line from me to the Sun. So I will need to check that the angle changes at different times of day and at different times of year, depending on the height of the Sun.
