Know you've already looked at the original source photo on the Getty Images / Hulton Library site, Jim. It's obviously a "colourised" and idealised version of the below, said to have been created on May 1 1919.
An alternate photo of the tram by the same photographer, also created on that date, looks to have been taken in the same location and is captioned: "Passengers board a tram between Shepherd's Bush and the Chiswick Empire." So if that is correct (and captions can be wrong), it narrows the site of the pic down to somewhere east of W4?