Erich,
I enjoyed the book. It's a little dense as to writing style, but that's a minor quibble and a matter of taste.
There are not a lot of photos, but there are a fair number of map illustrations showing the development in coverage of the Chain Home (CH) system, the squadrons, and their stations. These are all updated as the war progresses.
There are illustrations of the various scope displays and how to interpret them, as well as some diagrams of the placement of the various aerials involved in AI.
I think it's worth the price.