As we don't fly either type any more, it's safe to say that it was indeed 10 minutes for the F4 on UK QRA, 5 minutes for F4 Battle flight in Germany and 15 in the F3, although usually faster than that. The point about the INs is that they didn't require a full alight because they were aligned whilst putting the jet on state and then the paltform was locked in its aligned position so that it could be rapidly aligned during a scramble. We could keep certain parts of the equipment powered to reduce the warm up time.
The F3 had twin INs and took a little longer to warm up/spin up. The advent of Ring Laser Gyros did make a difference, but you were probably already at the point where getting the crew into the jet and the engines fired up was the limiting factor.
I was scrambled once in Ascension Island in 1982 where adrenaline took us from asleep to airborne in 3 minutes. I don't think I was fully awake until the gear was up! So Wideawake Airfield wasn't such an appropraite name after all!
Tartare, I'll send you a couple of links to my own description of QRA together with some old documentary film that should give you a good idea about it. PM to follow when I get a bit of time.
Courtney