I am flying with my wife and my 9 month old son in December from JNB to LHR, and was in the same predicament. My wife gets motion sickness so likes to face forward, so we decided to go for 64A and B, as we can use the cot, and it is at the back of the cabin, so therefore hopefully less intrusion on everyone else. Also close to the galley if we need anything during the flight. He will have also been on a few short haul flights, so will hopefully be used to flying.