You should see a wooden door on the right side of the image (Drag to the left if you can't, you should be rotated to the right of the image)

At the bottom of the pillar to the right of the door is a very small circular marker which is almost the same colour as the wall. It has some unclear writing.

Below the pillar, on the sidewalk, is a metal plate.

(Correct position for this note);
https://www.openstreetmap.org/note/3329171