English Handbook for christian Schools (BJUP)

I have found on my shelf something I had forgotten about,  a brown hardback book called, “English Handbook for Christian Schools”.

https://www.amazon.com/English-Handbook-Christian-Schools-Collins/dp/0890842795

I bought it 6 years ago when I first pulled my boys out of public school, it was recommended on Donna Young’s site, this was before I had discovered CM.

I have no grammar knowledge (I was not taught grammar at school) and so far have not touched grammar lessons with my boys AT ALL (Now 14 and 15)

Has anyone got experience with this book? Is it a good one to use? How is the best way to use it?

Thanks in advance.

Jo (in the UK)