There is a very good reason that they give you 8 page booklets, two of them and recommend that you spend only 70Mins total on the essays.
They want the standard deviation around an average page count (by average writers) to top at aproximately 8 pages. You write more and you are in serious danger of waffle and loosing marks in other sections.
Whilst I agree that the time they allow for MC, SA is generous (I took about 1 hour as opposed to almost two), the idea is not to skip over them, in many cases SA is filled with easy marks, easy to get with the application of a small ammount of time and easy to loose if time is sacrificed.
At 42 pages I think that someone is either a huge writer (eg low words per line), big picture person, memorised essay or they are gilding the lily somewhat. Quite possibly any combination of the above.