You are correct that you cannot do CAI-LHR-DXB-LHR.

You cannot reenter Asia after SYD on your way to JNB. The only transit of Asia allowed from Oz is to Europe, not Africa. However, you can fly QF SYD-JNB direct (although not in first as it is not offered on this route).

[This message has been edited by ExMo (edited Jan 21, 2004).]