The AFE statement represents the "conventional wisdom" on this matter.
The author of the PPL confuser probably constructed his explanation to match the CAA answer to the question.
But the question has since been amended.
In its current form neither the 30 degrees (AFE) nor the 25 degrees (PPL CONFUSER) nor the 50% speed increase will get you exactly the CAA answer.
But they will all get you an answer that is closer to the CAA answer than to any of the other options.
Looking further ahead, don't expect any book to be 100% correct. They won't be.