Enjoyed the book, both text and pictures, covering an little studied aspect of London history (as opposed to things underground, for instance, which is drowning in books at the moment).
One factual issue - on p165, when describing the changes to the electricity industry in the 1920s/1930s, the author talks about the creation of the Central Electricity Board (CEB) and its roles in introducing the early grid. However, it says "Using direct current (DC) as standard, again pioneered by Ferranti...", which seems highly unlikely given the issues with using DC for long distance power transmission, and Ferranti being a major proponent of AC (I think it was Edison in the US who was into DC)... The UK grid, initiated by the CEB, was of course 132kV AC.
Otherwise, one plea if ever updated - the book is crying out for a couple of maps, showing the location of the sites for both Power and Gas, especially given the discussion about the importance of the proximity to the river. Just simple, hand drawn maps would be great.
It would be pedantic to mention the typo where "sight" and "site" get confused.....
None of which should stop you buying this book, it's got some fascinating detail (especially around the history of and competition between the companies as the market got established).