Apprenticeships, Skills, Children and Learning Bill

I, too, am interested by the use of the term "over compulsory school age". I thought that "compulsory school age" was a historical concept and that what we now have is compulsory education to the age of 18. Thus, this usage would appear to be inappropriate or at least ambiguous. Where does it leave 17-year-olds and 18-year-olds?