The flight to London took about eleven hours. We had picked London because we wanted to have the fewest number of flights between home and Cape Town. Johannesburg gets the vast majority of the international flights coming into South Africa, and we had heard it was a nightmare, so we wanted to avoid it. Unfortunately, as our itinerary kept getting tweaked, we ended up having to go through Johannesburg not once but twice – once for going from Cape Town into Botswana (when Air Botswana decided to just cancel its direct flight from Cape Town), and once for going from Victoria Falls to Rwanda (which requires three legs minimum).
We got into London in the mid-afternoon, and after hearing and seeing how it's always dreary and rainy in London, we were happily surprised with sunny and clear weather. We had almost a four hour layover in Heathrow, which we had heard was just above the minimum when changing terminals. All the flights to and from LAX go through terminal 1, and all the flights to and from CPT go through terminal 4.
From what we had heard, we were expecting chaos at the terminals and in security, but it was more like a church service. There was almost no noise at all, certainly nothing like in the States where someone from security is screaming at you every five seconds. There were signs and video boards (without sound) telling people what to do, and unbelievably, people could actually follow directions without being yelled at and demeaned.
After making it through security, we had some British food at a pub in terminal 4. It was nice enough, and enough food to tide us over until Cape Town. Our flight to Cape Town was a little late in taking off, but it was not a big deal since we had no connections after that. Both of us were asleep well before we got to the African continent.