Definitely analyse the extras. The 10/10 Physiks knows would have been incredible writers that couldn't have fairly been given a nine, I'd say. Rule of thumb, anything that appears on the exam should be analysed; if there's two pictures, do both. If there's comments, analyse them.
I grouped the comments for last year's (as a prac this year) into one paragraph and sort of did a comparison between the indiviudal mini-arguments and language technique (I found there to be generally one large technique) and how they reinforced or detracted from the writer's contention. It doesn't have to be written by the writer to reinforce the contention of the piece if it is included in the next publication of the magazine or in comments of the blog etc.