Originally Posted by ReelChief
Of course, if business isn't good it may later get pulled and that is what you seem to be referring to. If that happened, I'd guess that they would require you to fly MRU-LHR but then if they allowed MRU-LHR-JNB to replace MRU-JNB, that may be what you are hoping for.
I would be delighted if they did an invol rerouting from MRU-JNB to MRU-LHR-JNB! But I'm worried BA LON wouldn't authorise that. It'd be more of a case of refund the ticket as travel hasn't started yet, as per
number_6's experience above.