Originally Posted by number_6
Absolutely not, unless Comair is also serving the 3 gateway cities (and I suppose they must be serving at least one). The 2nd entry into Africa is only allowed to the 3 specified cities, so you cannot fly LHR-JNB or LHR-CPT (or MAD-JNB, etc) if you originate in MRU! Very important and inconvenient rule (unless this rule has been changed in the past week).
The return to Africa has to be LHR-ACC/whatever you want to do in Africa, probably surface segment to JNB. Likely to be a somewhat expensive one-way ticket (or a long and gruesome land journey).
edited to add that I almost always go eastbound (it is so much more efficient), thus I cannot do HKG-JNB-MRU or SYD-JNB-MRU but have to re-enter from Europe. For westbound the new Comair service does solve the MRU problem nicely, but can it be booked yet?
So your "absolutely not" really meant "absolutely not for what I want to do" but doesn't preclude anyone wanting to do a RTW going MRU-LHR-LAX-SYD-JNB or LAX-HKG-JNB and onwards to any of the Commair ports I mentioned? And as my post mentioned nothing about flying LHR-CPT or LHR-JNB I'm not too sure what exactly you are saying is wrong with the info given in my post.