"For those of us who aren't numbers people to start with, pouring over a black-and-white grid"
- Those of us who are numbers people have probably also learnt how to spell poring

I would find this exercise perhaps more persuasive if the actual tables were better organized: for instance no.7 has a list of items which appear to be in no particular order, not even alphabetical, and the figures associated with them show no great pattern. Had you thought of ordering the items by their total number or by the outstanding number to be checked (which appears to be the principal point you want to make, judging by the coloured bars) ?