Naked, I know that much.

If my understanding of physics is correct, they'd have to be slap bang in the centre of the reflected image (assuming a perfect sphere), so somewhere on the framework of the corner of the building.

I think standing near the red things in the middle of the reflection. Look at the size of the forklift in the reflection for reference.

The center line of lights in the reflection is higher than the location on the wall, which leads me to believe that the photographer is just above vertical center. * Due to the nature of photographing a sphere horizontally they would have to be exactly centered.

I think they're somewhere around here

i noticed that in the OP too and it confused me a bit. then i noticed the dark corner bottom left, which is probably a bit of the wall of the dark room the picture was taken out of. that's why the photographer isn't in the reflection.