A miniscule copy of this picture appears in David Brown's Southern Electric Volume 1. David has told me that the image in his book was derived from a postcard size print which probably originated with John L. Smith (Len's of Sutton). This version is derived from the original glass negative and benefits from bing a far more detailed original image.
This is the LBSCR's overhead electric depot at Peckham Rye photographed in 1927 but the depicted vehicles, far from being electrically powered, are driven by petrol fed internal combustion engines. Both are Daimler powered with Dick Kerr bodywork and according to David's caption no. 1 on the right was purpose built whilst no. 4 was a conversion from passenger stock. Note that, even this far into Southern ownership, both are still adorned with pre-grouping livery.