uniz care about your GCSE results
Most importantly its english, but as your get more specific with courses, they look at the core subjects, e.g. art for an art related course.
English is a main requirement, especially for all you fellow international students. Even maths for some odd reason, but that could just be for my course: architecture
but places like oxbridge indefinately look at your GCSE results, i mean they have a column in their apps that even ask you which modules you are planning to resit *AS*, and if so when, and they even ask you what you mark was for individual modules... so they really care!
but if you are predicted for low grades in maths, and esepcially english in GCSE, pump that mark up!