You friend may be a draughtsman, but that does not make him, or yourself right. I also disagree with what you say that “the roof of the back tram is correct to be the roof of the front tram”.
I have also enlarged this photo too, and as oldMohawk confirmed in post #422 the levels on the trams don't seem to match by a small amount. It was this prospective error or parallax misalignment that made me think it may be a composite image.
I would say that there are most likely two trams both facing the same direction. People getting ready to jump off the back of trams and busses was a regular occurrence. In fact, did it myself a few times.
I think that this image was taken with a camera and lens with quite a long focal length. This may explain why the perspective is compressed and the shops to the right look relatively straight, when we know they curved away at the corner of Slade Road.
This has been a fascinating discussion, that will hopefully continue. It is captivating how we interpret the past. I quite often hear people talk about historical fact and will refer to the primary source as fact. This post goes to show that even with a photograph, different people see the image in different ways, and will interpret the past in ways relating to their own culture, education, social standing and experiences.