I have a painting of this signal box that shows the door on the left hand side however all the black and white photos show it in this location. The bricks look like a slightly different grade around that area so it probably was moved for some reason. If I find out I'll let you know.

I also bought a book this week about Bishop Auckland during the 2 world war by Barbara Laurie, not much information on the station but an interesting read none the less.
regards
Derek