Just as a quick follow-up to the post on MLE discourses, you might find some of the following discussions helpful for the wider AO2 part of Section B Question 4. This is where you'd use ideas from language study - concepts, theories and research - to respond to the ideas raised in the opinion pieces you'd been analysing in Question 3.
Rob Drummond on 'Multicultural British English'
QMUL's Linguistic Research Digest on MLE
I thought this was quite a useful paper too. It looks at students' attitudes to MLE and media representations of it.