Can't help thinking that "Ticket changes allowed for free" is apt to mislead.

As an experienced traveller, I know that this means there is no change fee. However, for most people changing the date/time of flight will lead to a reprice of the ticket and the cost will be dependent upon the availability on the date the change is made. Close to departure the actual cost of changing the ticket could run to hundreds of pounds. Very rarely will it be free.