SureBluff, instead of splitting up your essay or your work by word limit, it would be wiser to split up what your going to write about by issue/topic. therefore you write however much is required to fully assess the issue in each paragraph. the weighting of a frontline episode should be slightly more than a related text which should be used to support the arguements you make in regards to the "truth".
In regards to the Board of Studies asking for a particular prescribed text they have done it before. They can specifically ask for a certain episode, or for a certain poem (in one of the other modules) for example. There is nothing in the syllabus that says that they wont/cant. yeh, they'll have a list of texts that you can chose from, but what if they specifiy.... keep in mind that they have the power to do so (and they have exerted that power before)