A great thread and got me thinking about the fabulous documentary "The Last African Flying Boat".
The Flying Boat Forum from www.seawings.co.uk ? View topic - Trans African Catalina Trip
There is a write up here from one of the crew of the PBY in that documentary. They retraced the old flying boat route some time in the 1980s in an attempt to start up tourist flights. They stopped off at Abu Simbel along route, just downstream from Wadi Haifa.