Did the agent actually see if the space could be booked, or did they just look for availability? If LAN is using married segment availability for partner award bookings and making those segments only available to some partners and not others, I believe that would be a pretty substantial change from how things have operated in the past. BA is well known to show phantom availability for LAN awards, however, so unless the agent is able to book the space (or you are online), it's probably more likely that the space is not really there.