My hopes for a London Russel Group Uni

I'm currently in year 12, just getting started with my a levels. I'm aiming to go to one of the four London Russel group Unis, which are UCL, LSE, Imperial and Kings. I am willing to apply to any course from these unis that are maths, finance, business, accounting or economics. I am currently doing Maths, Economics and Business for my A levels. Due to lack of motivation and a lot of procrastination, I did horrible in my GCSEs, as I only revised a maximum of about 3 hours per paper the night before..
My GCSE grades for context:
7776666664
Maths - 7
DT - 7
English Lang - 7
English Lit - 6
Bio, Chem, Physics - 6
Geography - 6
Drama - 6
German - 4
I understand these are way below any applicant that gets accepted into these unis, but is there any way I can still get in. Theoretically, if I were to get AAA in my AS levels, and be predicted 3 A*s, and then manage to get those grades, would I have any chance of getting accepted into these unis, or would I just get rejected.
I'm asking because I'm not too sure if I really want to go to Uni, and if I do go I would like to go to one of these Unis. If it isn't possible, I can focus on other areas rather than attempting to try and get 3A*s at A level.
Can anyone suggest any ideas and whether I would be able to get into these Unis if I was to get 3A*s