I've just finished 'Ida', and enjoyed that read just as I've enjoyed the others in this series and others you have written too. I looked too at some of the Qs and As and noted that in one response you mention how Uhtred is getting older now so perhaps confused. That might explain the slavery point, He claims that he was sold into slavery by his Uncle. My memory of the previous books is that this isn't so - or is it my memory that fades?
His uncle arranged his capture . . . and paid money. It wasn’t a direct transaction, but in effect he was sold!