The staggering flaw in the "Big Airfield" argument is that not one of them has a Secondary Instrument Runway. You can bang on all you like about "economies of scale" and "cost savings," but there will be tears before bedtime when, for example, RAF Scotland's one remaining airfield goes Black, and 'n' aircraft have to be diverted to another, already over-utilised airfield.
It could end up with half a dozen fast-jet crews banging out, because there are Transport aircraft, Nimrods, Sentries et al with larger numbers on board holding awaiting recovery. The ejectees, probably with some injured, would then have to wait their turn for the depleted SAR response to rescue them all. It simply doesn't bear thinking about.