This "sitting" nonsense is actually EASA's fault
The problem is not with the 'sittings'.
My understanding is that EASA originally intended that there would be one exam of 120 questions, with six attempts (sittings) but then the UK CAA decided, without any consultation with the people who produce the books/CDs, to introduce their re-division of the subjects into nine exams and the EASA 'six sittings' requirement at the same time.
This is partly EASA's fault, as they allowed the National Authorities to devise their own versions of the original requirement, and, not for the first time, the CAA have come up with the most administratively complex and onerous version.
They originally defined a 'sitting as a period of just one day! Then after howls of protest, were kind enough to extend it initially to three days, then to the maximum allowable under EASA of ten days.
Itchy, you are right . The books/CDs still cover all you need to know, but the content of the exam may no longer come from the book/CD with the same title.