What about the 11+ Explained: Non-verbal Reasoning: Essential Skills and Strategies for Success by GL-Assessment?
I have a copy of that book and the VR version. Very nice gentle familiarization
as approved by GL with some useful guidance on student stress, but!
Not as comprehensive as a proper VR or NVR how-to-do book, for NVR I would go for AE books 1 and 2.
The GL book is worth buying as a very gentle introduction to NVR and for using as required for stress and strategy, but it ain't a full blown guide.