I figured you it was due to the guard's van or luggage van traditionally being at the end of British consists, just thought I would point it out since I always strive for 100% accuracy or as close to possible, and in America I like to ride in the saloon carriage or 1st class carriage which is commonly at the end, so I notice the "tail carriage". I have made that mistake too though with a combine carriage.Interesting question...I kind of just put it the end automatically. In Britain, it is standard practice to run with a "brake" or "guards" van or coach at the end of the train, as you said. So I guess I'm just used to it.
The shot is more about atmosphere than realism though, but well done for spotting that.
Saturnr