Jaguar's gone, and isn't coming back. I remain of the opinion that it was retired too early, and had useful life left in it, but it's gone, irrevocably, and any whingeing about it now would be as unproductive as WEBF's 'bring back the SHar' campaign.
I would not advocate expanding the Tornado GR4 force, either, even if airframes were available, nor would I spend disproportionate amounts on extending its service life or delaying its OSD.
But I would not spend £1 Bn on extending Harrier's life from 2013 to 2018.
And I would not spend the amounts required to procure, deploy and sustain two CVF and an appropriate number of F-35Bs which will represent an undeniably impressive, but unjustifiably expensive, unaffordable and inefficient means of projecting air power, and one which will unbalance our forces by distorting spending.
It doesn't help that no-one can give a straight answer as to how much F-35 will cost (let alone a firm, guaranteed price), or as to exactly what capabilities it will have.
If we need more than 12-14 FJ squadrons (six or seven Typhoon, six or seven Tornado GR), then I'd be acquiring Gripen NG to augment Typhoon, or perhaps (in the 2023 timeframe) a small number of F-35As to replace the Tornado.
But even as an admittedly air-minded chap, I'd suggest that SH, tankers, recce and SEAD are higher priorities than further FJs, whether JSF, Rafale M, F/A-18 or Gripen NG.