Each Oneworld carrier agreed to paint X% of their fleet in OW livery... BA say that the 747's were due a re-paint so made the decision to do them...
Short Haul are the very poor relation of BA, so they would never bother to paint any of our aircraft... Same as when they put the "Keeping the Flag Flying" titles on some of the 777 aircraft... Would never think that hundreds and hundreds of short haul crew came in to support the operation and operate many short haul flights.