Help concerning uni, A levels & GCSE's

Hi all,
I want to study law at a top law uni preferably in London or Durham (I know I can't get into oxbridge) In my first year of college I studied a 90 Credit BTEC Diploma in sports and achieved a DISTINCTION* DISTINCTION* (equivalent to 1.5 A levels at A*) however I am choosing to change courses in my second year and start a fresh completing A levels. I am going to be studying History, English literature, Relgious education and Drama. My dream is to be a solicitor and secure a training contract in central London preferably with a top law firm, I am determined and am going to work hard however in earlier life I did not perform to the best standards and achieved the following GCSE's-
English language B
English literature B
Maths C
Science C
Science Additional C
Geography E
BTEC Business Pass
Drama C
IcT B
RE C
BTEC Sport Distinction

So as you see I underperformed however at A level I am going to turn this around and hopefully Achieve at the bare minimum of AAB (more likely AAA) so will my poor GCSE's f**k me over for uni? As previously stated, I am looking for top Law unis such as UCL, LSE, KCL, Durham ect can anybody help? Will my 1st year of further education also effect me negatively due to the fact I did not participate in A levels? Any help is appreciated.