Ucas help

I started cardiff uni doing politics this september, dropped out recently and am now reapplying through ucas to do law. i've set up my ucas account as an individual and not with my sixth form, today i paid to redo one of my history papers as an external student with my old sixth so i put on my ucas that i am still there until 2016 (as an external student) all i need is a reference from my head of sixth to send it off. But, i was wondering do i need to make a new ucas with my school or can i just keep the individual one as i have put on it that i am technically still at my sixth also, i'm only redoing one paper and cardiff probably still have me on record?