Thanks for the replies.
It was me that made the booking and I really should have read the information more clearly. It seems I let my reputation in the family as a "travel wizard" go to my head
So I have swallowed the loss and rebooked her, this time through a TA. Niece's new reservation now reads "CASH" so she should have zero hassle at check-in. I will also cancel the original reservation so she doesn't get auto-deduplicated !!
No refund on ticket #1, so a live and learn - at least I'm only out a moderate amount