Hi, If like me you've been struggling to add your Advance Passenger information when Logged into BA.COM - you may have been unable to complete and save your detail. I was getting messages back about correcting contact data etc.
If you log out of the ba.com portal and then browse to the 'Manage' tab , from here you can enter your 6 character booking code and the surname of the passenger who made the reservation. You will now be able to complete your API.
The Trick here is NOT to login to the BA.COM portal.
Hope that helps.
Mr.Boo