UK Risk Internship with Masters?

1. Some places will ask for ABB at A level or A in A level maths, but most places don't and I don't think they care that much about A levels. Your degree and masters is more important imo.
2. Master's students do - I've just done a masters at a top 30 UK uni in Financial Risk, so nowhere near as good as LSE, and that didn't prevent me getting a telephone interview at Morgan Stanley for Sales and Trading summer internship (although I have interned there before in back office and Bank of America in Middle office, so that might have helped). Didn't get the interview though. Some places may say you must be in the penultimate year of study, but I feel like most places don't really care, as long as you haven't been working full time already. Don't lie on the application form, it will come out when they do referencing if you're offered a place. And apply now, many places are already open.
3. I did my masters in Financial risk, and so have been looking for risk graduate positions, which have been hard to come by. I would imagine they get less applications for risk, but there is also less positions, so it's still difficult to get, and I don't really know the answer to this question. I should apply to both though if you can apply for more than one program, which will differ between banks.

Edit: Also don't be afraid to apply for full time positions, you won't automatically be rejected because you haven't done a summer internship, but I personally have avoided applying for graduate schemes at any of the bulge bracket banks since they seem to fill their graduate intake with summer interns so it's a bit of a waste of time. For smaller / less well known banks you could have a good chance of getting a full time position straight away.