You should probably put a few down (at least 2, I think they have 3 spaces). Put a recent employer or if you haven't had a job put down a few of your teachers as well and maybe one or two people that know you well (eg. family friend, uncle/aunt etc.) or you could even put your mum down and just change her surname to her maiden name (don't do this but).
I'm pretty sure they rarely check your references, and the only time they would is after a group interview or one with the store manager. But they usually don't bother as it is too time consuming and if they have already seen you face-to-face, why ring someone else up?
