Originally Posted by PresRDC

Not true. There is an exception allowuing a second transit through Europe if you are connecting to one of the African destinations that does not have any OW service other than to London. Examples include Dar es Salaam, Nairobi, Lagos, Entebbe (and a few others).

I am routing eastbound and did MRU-LHR as my first flight. I will end flying EZE-LHR-NBO (originally, I was routed to end in CPT, but it was a mistake made by BA in MRU and was later caught and corrected by AA -- fine by me, I didn't want to violate the rule).