Thanks, Keith!
It would seem that the Red and Green hydraulic systems powered the AC alternators for the radar and missile systems - and that there was indeed a heat exchanger in each engine fuel feed line, the purpose of which was to cool the fluid of these general services hydraulic systems as well as to heat the fuel for filter de-icing.
What a very complicated aeroplane the 'Vixen truly was!
Last edited by BEagle; 3rd Aug 2016 at 14:08.