We built a bloody great airfield on the islands after the last time, stationed four Typhoons on it and put a bunch of soldiers and a few missile batteries round it to stop anyone knocking the runway out in the event anything kicked off. It's specifically there to allow the islands to be rapidly reinforced should an invasion happen/appear imminent. We could probably have a dozen Typhoons operating out of The Falklands tomorrow, whereas even if we had a carrier and the Harriers to fly off it, they'd take weeks to get there. The Falklands effectively
are an aircraft carrier.
The whole carrier thing is stupid, but it's not a factor in The Falklands.
The Argentinians successfully invaded the islands last time a) Because Maggie gave them the impression she didn't give a feck about the islands and b) There was pretty much nobody there to stop them when they did. Neither of those things are currently true, nor will they be for the forseeable future. I can't imagine any sane Argentinian government deciding invasion is a good idea (and the current PM is a bit of an opportunist but she's not insane).
If Cameron is hoping for a nice war to boost his popularity before 2015, he's going to have to find it somewhere else.