Spaz, details here, page 34, the wingman returned to Tindal upon reaching min fuel, no mention of Gove. I see you have referenced the link yourself previously.
http://www.pigzbum.com/accidents/sif...he-evidenc.pdf
I have some extremely vague recollection that there was some problem with the Hornet pilot to airframe oxy connection at some time where it could become unplugged, may be the memory turning to mush.
Then again, perhaps he recognised the onset of hypoxia because of the now recognised issues with the on board oxygen generation system and removed his mask, who knows.