"Your flyer and the publicity say if one person is travelling, it's valid for one day only and to date one box"
I don't think the flyer is specific about only one person travelling, but I can't remember for sure.
I certainly mis-remembered the email they sent, it actually says
andYou have won two free train tickets with Northern Rail.
(no mention of two people needing to travel).Congratulations, you are the lucky winner of two free day return tickets to anywhere across the north of England with Northern.
And they say that it may take a month to get a reply from emails to customer services!