Checked in for BCN today at First Wing and asked about AUP for LHR tomorrow which we are on as part of a BCN-LHR-MEX. Was available and agreed to the 299 but wouldn't process on system as before checkin opens. Called flight manager and he said just wait until checkin opens and then go to guest services and process. Went and by that time only option 1A and 2K. Decided we'd rather stick with our 7A and B for the 11.5 hour flight as we like to talk with each other quite a bit. Shame was thought it was a good deal for a pair in the middle.