Mathematics Masters Chances?

Hi, I was wondering what my chances are of getting accepted to a high ranking university for maths masters, like KCL, UCL, Imperial (or even some slightly lower ranking ones like QM or Surrey) if my undergraduate university that I'm doing my math degree in is although accredited, is however an ex-poly, low on rankings and is focused on the 'easier' applied math course.

I was reading some other post very similar to this for Oxbridge and it said an undergraduate math course like mine had a 'real danger of not being sufficient preparation', which was my initial worry and it makes sense. I was wondering if that condition applied to the other universities I mentioned. Also is there anything I can do besides self preparing by reading some books and teaching myself some of the required material, which I don't even know is sufficient or helpful enough for my application.

Some other info: I'm starting my final year in a couple of weeks and I got 80% on average in my second year without really trying too hard and my A-Levels were A*ABB (Math, Physics, FM and Chemistry) if that matters. If you need any other information please let me know.

Thank You!