Hi, I was in a similar position to you as I chose a very wide topic that I am certain has been done before. You choosing a topic that is not 'original' does not really mean anything in real terms. Practically everything has already been done before or has been alluded to in some way. Unless you are planning to create a brand new, never before seen theory this is the position of everyone doing EPQ. I would just make sure that you really specialise in your project and go into a more niche angle - this shows greater depth and will single out your project as one that isn't attempting to bite off more than it can chew. For best marks make sure your evidence is strong - the dissertation/artefact is important, but your data logs, diaries, conversations, diagrams anything of the sort are essential so prioritise that. You are not being compared to others, strictly, it is more the quality of your research and analysis that is being marked.