Note that I have not received the refund yet, but it will be sorted. I'll keep you updated just so you know what to roughly expect. Best bet is to contact Customer Relations, explain the situation, and state that you want a refund (and will purchase again later - can't hurt to fib a little).
For CR to arrange a refund they pretty much need to speak to the manager of a store and ask them if they're willing to offer it. Otherwise, it'll be refunded through AppleCare. In my case, I actually had £85 worth of vouchers spent on the phone, which they'll also be refunding me in cash (if they can't get the refund sorted with my local store). This said, I have a feeling it'll all be done through AppleCare anyway.