My subject area is different from yours, jennypenny, but my Masters dissertation included a short reflective chapter, in which I explained things like my background, values, interests and so on, and how these might have impacted on the research questions and focus I chose for the research, looking at both the strengths and potential weaknesses of my particular perspective. It might be worth asking your supervisor's advice about writing in the first or third person, as supervisors and institutions vary on this one, but I definitely used the first person when doing reflective writing as I'd have found it far too awkward otherwise!