CTL, thank you for that.
I have also flown through Lisbon, from Johannesburg when I first went to Gateshead Yeshiva. But that was on Air Portugal aka TAP. On my way back I was in transit for a day and a half, traveling Newcastle-Heathrow-Lisbon-Kinshasa-Johannesburg, from Monday morning to Tuesday afternoon.
I think SAA’s main stopover on the Europe route to avoid Africa was Ilha do Sal, in Cape Verde. They still used it later on westward flights as a crew changeover point on the flights to Atlanta. If i remember correctly, the usual route to Tel Aviv was via Ilha do sal and Rome (?) and took 22 hours. After Apartheid, they flew direct and it took 6 hours.