Originally Posted by
ringbark
HRE JNB arr terminal A at 1915
JNB LHR dep terminal B at 2045
Don't worry about the terminal A/B bit - that is only relevant when you have to check in (one end of terminal or the other); you will be in international transit, so stay airside and just go through a security check to land you back into the international departures.
Very easy transit, no worries on timings.