We found the building on Google Street View dated 2012 but by 2014 it was gone. From the design of the building and the dolphin relief we'd guess it was built c1930-40. It appears on a 1950 map.
The Underground Map have a photo (c.1900 from the clothes) from the London City Mission magazine captioned "The location became the Dolphin Pub". It is also labelled "Corner of Bangor and Sidar Road", see this 1896 map for the streets. We note that the buildings in the background of the photo don't tally with the buildings that are shown to be there on the map and we wonder whether the corner shown is actually that with Crescent Street and not Bangor Road. But, assuming it is Bangor Road, then the building on the corner site is a typical Victorian corner building which could be a pub named Samuel Spencer, but we can't find any more information.
