I'm not an arts student, but it sounds like you already have the ideal educational background, and I'm not sure another MA would improve your chances.
What might do is having some research experience, of some kind. Is it worth trying to find some kind of researchy job, even if not in an academic sector? Could you try to get any articles published while you wait to reapply (even if not in academic journals)?
Regarding your first attempt, was Oxford the only place to which you applied? It might be worth (a) asking for feedback, so you might be able to produce a stronger application for next time, and (b) casting the net a little wider.
Good luck!