Unlocking Freeview Boxes?

I have recently been given a Digilogic Freeview set-top box (model no#DSTB1000) and the previous owner (my brother!) 'locked' the menu page as he wanted to keep a parental control over viewing for his two young sons. I have managed to set up the box easily enough for viewing but need to access the Menu so that I can switch from the currently-showing 7-day EPG to the Now-and-Next EPG with in-vision picture. I also want to re-install the channels again as we now have Dave+1, Ch4+1 etc. My brother can't remember the number to unlock the menu; is there a default or hard reset that I can do to clear this, please? Worse still, we can't find the instruction book nor can we find one online as I think the product is a Tesco 'exclusive'.