Regarding the Martel missile, I was told by one of the people involved that after they had fitted it to the Vulcan, somebody read in one of the tech manuals that the missile couldn't withstand prolonged exposure to extremely cold temperatures (i think the missile was originally designed for the low level role)
I can't remember the limiting temp nor the time limit but it ruled out any flight from ascension to the Falklands.
Whilst you've asked about the Victor/Martel combination, I think this covers it.