I actually completely disagree with the poster above. You won't be a 'strong' applicant but you could still compete. There was a user on TSR last year who got roughly AAABBBBCD in his GCSE's but they were top 10% in his school. He then achieved AAAB, had good interviews, did well in the admissions test and now studies law at Cambridge. Cambridge specifically puts less emphasis on GCSE's than most universities. I think you'll be fine, just work hard!