iPod Touch 5th gen pass code

My 7 year old daughter got hold of my son's brand new iPod Touch, which I hadn't even set up yet, and managed to add a pass code, I'm assuming on the initial setup screen.

I've tried a restore while plugging it into iTunes, but iTunes continues to tell me it needs the pass code.

Please help, what do I need to do? Should I make an appointment with the apple store?

I realise there is a lot of theft regarding these things. This is a genuine query.

Thanks in advance.