Hehe, you repeated the same mistake as I did in the tutorial. I was in rush so I accidentally used tire bump map as diffuse. But you should do it better ;)
Other than that, do you see how background behind window is blurry on your first image? Just take edge of your ground plane geometry, and extrude it up so that there is some shadow catcher geometry behind those windows, it will map shadowcatcher on top, and your backplate will show through windows too ;)