They are indeed very similar to the Leyland escape van and pump appliance depicted on the London Fire Brigade website's historic appliance section - as being typical of acquisitions in the second decade of the last century.
The LCC London Fire Brigade Notebook for 1913 also includes a photograph of a Leyland pump appliance, which is identical to the unit in the center of this photo, except that it is lacking the hose reel behind the front seat. In addition, at this time, the London motor pumps did not carry any ladders on an overhead gantry, either...
The reciprocating piston pump was rated at approximately 450 gpm (2050 LPM) at 7 AT.
In that year, London had a motor pump at 24 of its 63 fire stations, and was considering the cost of a program to replace all its horse drawn units, but this plan had not yet been adopted. The main reason was that the estimated cost was a staggering one thousand pounds per unit!
Added by Rob Johnson on 10 January 2018.