Surveyed yesterday. https://www.openstreetmap.org/node/321655203 is present; I couldn't spot https://www.openstreetmap.org/node/321655205, but it's supposed to be in the same building, which is clearly a service building. I couldn't spot the other two, but they might very well be within the building, as there are no visible entrances to any substation from the outside.

I will ask for a second opinion in the OSM BE Matrix room.