I wonder if it's the same reading diary we got.
I was very suprised to see the new home reading diary full of hints such as "encourage children to: look at the picture, look at the starting letter, reread and make their best guess, stretch the word, read on."
We are well past that stage anyway (DS can definitely read his chapter books without looking and guessing from any picture), so I didn't think those particular tips were relevant to us anyway.
The reading diary (which is the same for all children in reception, Y1 and Y2) is from a company called Kluwell, and from googling it I found they are used in Australia and NZ, so might not be in correspondence with the latest UK curriculum.
Although, from talking with his teacher, I got the impression that the point of the diary is to keep a daily record with comments on every book they read, so that they get rewards after 25 days, 50 days, etc. More to encourage daily reading rather than anything else.
It's a bit confusing though. Not sure whether they are advocating guessing or not, and cannot really say that I ever got that advise from his teacher when DS was in reception.