Since when did the word 'universities' become interchangeable with 'Oxbridge standards'?
Your A Levels are fine for History and you obviously enjoy them; all that matters is if you meet those entry requirement: an AAA in History, Sociology, and Politics for example is far more impressive than an AAC in History, Politics, and English Literature, especially if the requirements are AAA-AAB.
If you enjoy Literature and you're good at it, then, by all means, take it. I'd swap it out for the subject you're least comfortable in.