How is stuff weighed??

Hi everyone!

So I'm studying Politics and International Relations at Kingston (undergrad) and absolutely need a 1:1 to do my Masters at Oxford which has always been a dream of mine. I just don't know if I'm on track.

So I believe that in terms of weight by year its:
1st year = 0%
2nd year = 20%
3rd year = 80%

I have gotten low and mid 1:1s for all the essays I have submitted this year except for one which was a high 2:1. I have 2 more essays to submit and one exam left on the 9th of May. I am horrific at exams but this module was compulsory this year - no exams next year, thank God. But I was wondering if I took it easy on the exam, maybe pass or get a 2:2 or something, will this affect my overall chance of getting a 1:1 in my degree? The exam is 50% of the module which is a 60 credit module (we have to do 120 credits every year).

I also would like to know how the overall degree is graded and how much my dissertation would weigh in 3rd year? I have been trying to find it on the Kingston uni website but have been unsuccessful. The thought of writing a 10,000 word essay is very scary and have been dreading it these last 2 years, so I want to know if I don't do as well, can I redeem myself in other modules/assignments?

Thanks for any help