McKay employed Henderson to get Sala to Cardiff in time for Sala to join his new teammates in training the next day. To add to the complications, McKays sons were on City's books at the time and soon disappeared from the club (Colchester for one of them, I think) after the plane went down. McKay was after his slice of the cake and wanted to make sure Sala's transfer went through. In that respect Nantes are right to want their transfer fee and aren't liable IMHO.