This should be the degree course page:
https://www.kcl.ac.uk/study/undergraduate/courses/accounting-finance-bscUnder entry requirements, you should see:
Required grades:
A*AA
Please note that A-level General Studies, Critical Thinking, Thinking Skills and Global Perspectives are not accepted by King's as one of your A levels.
Must include grade A in Mathematics.
Notes:If you are taking linear A-levels in England, you will be required to pass the practical endorsement in all Science subjects. This is with the exception of private candidates who are unable to take the practical component. We do not consider the EPQ at any point of the assessment process.
I cannot see a section of GCSE grades, so I don't think they would care about the GCSEs for the above degree.
Key thing is that you have A Level Maths. You then need A*AA grades in order to stand a chance. If you have higher grades, so much the better. Beyond that, you would pretty much need to work on your personal statement.
There is no mention of interviews or entrance tests, so your grades and personal statement are all you have to go on for your application.
I have a more interesting question though:
I you don't intend to go into academic research in accounting or finance, why are you doing a degree in accounting and finance? It's going to be much quicker, easier, and cheaper to just go straight for the professional qualification in accounting and apply for a job/apprenticeship with an accounting firm or in an accounting role.