Often landing in Doha or Stanstead there was a ACJ in private livery and Qatar registration.
Many times, in Doha, there were 1 or 2 757's in same private livery.
Finally at UK end, ran into crew in Ops. The ACJ was only for the wives weekly shopping run to London, and 90% of what came back was from Harrods. The rest was in hand carry, very small ornate ribbon-wraped boxes.