Don't forget that the area you live in affects the insurance too.
My old Mk2 16v was costing me about £750 fully comp with elephant in a decent area of Nottingham, then moving to London and changing jobs put it up by £100.
One trick a friend did with his Elephant policy was to insure his car at his parents address, but to tell Elephant that he keeps it overnight at his address in London.
You can't do much about your postcode, but that little trick can work, especially for students.