If you have a decent MA, and some work experience in research (especially with some publications), that might make up for your undergrad (which I think would equate to a 2:2 in the UK?), but that's no guarantee. It's extremely competitive at the moment for funding, so while you might get a place (and no harm in applying, or at least talking to admissions tutors), the difficult bit will be funding. A lot of that depends on who is looking at your application. I have a pretty standard academic record (decent 2:1, merit on my MA - though distinction on my dissertation), but got my funding on the basis of several factors; a) that i worked in research for several years and had some publications and b) could show a clear interest and passion in the area i wanted to research. However, my supervisor had to really fight to get me the funding, as I went up against someone who had a 'perfect' academic record (1st, distinction etc), though no clear research experience. for my supervisor, I was the better bet, for the other admissions tutor, the other girl was. In the end, she was nominated for funding, but turned it down, while I got mine a different way. i was lucky, because i had someone who believed in me, and my project, but you'll always be against someone with the perfect record, and that can be hard to beat.