Loads of people have just started again at our school becasue of that...they got D's and E's and were havign to resit all the modules to get where they wanted to be and our careers advisor told them to start again and they did.
Its your personal statement, if it is on it just write that you made the choice to redo AS and why and maybe they'll see it as you dont give up and are determined....
I dont quiet get this cashing a grade in but i think at end of it all you only get the highest grades in the modules all the thers are forgotten so it wont exactly matter
does that help or make any sence?