Some nostalgia here. The incident where a deranged passenger got onto the flight deck of a LON - NBO flight was just before New Year 2000 (I think). Several 'famous' people were on the flight, one being Bryan Ferry (Roxy Music). The passenger was a Kenyan student and I recall he somehow got control and the aircraft lost several thousand feet before the Captain stabilised things.
As stated, the BA flights between LON and JNB and many others used to land at NBO southbound in the mornings around 0700 and then northbound at night to benefit from the cooler air. Iberia at one time had a flight scheduled to depart around mid-day for Madrid, needless to say it was not a great success commercially!
The airport was then called Embakasi and was a bit of a dump but it was always exciting to land there southbound, specially with a SA passport or SA stamps in any passport. That first kiss of the wheels on African soil meant you were truly on the way home. My worst experience was landing, landing, landing, landing, landing ..... on an Alitalia DC10 - we bounced about 5 times.
Somewhere I have some photos of those days, if I can find them I'll post them.