Incidentally, I doubt Argentina would make a push for the Falklands if this is the mid-'80s. The politicians and the military don't trust each other, at all - any invasion preparations could become preparations for a coup. In 1985, incidentally, significant numbers of Argentine military personnel were being arrested on account of having committed atrocities during the Junta period; worse, there was a lot of internal discontent within the military, with many lower-ranking officers believing that they were being scapegoated by the higher-ups. Besides, any moves on the Falklands would be tainted by the war having gone so badly, and having been connected to the Junta itself.
You are of course, absolutely spot-on when it comes to explaining the mess that was Argentina in the mid-eighties in OTL. In the
Protect and Survive universe, however, the rising tensions since about mid-'83 have led to a much more militarist atmosphere (this is not unique to Argentina - many neutral nations, even far away from the battle-zones, are looking to strong, right-wing leaders to protect them - this is both down to increasing anti-communism and the fact that these guys are seen as the country's best chance of survival if the war that seems more and more inevitable each day is to come).
The outbreak of global thermonuclear war has had a profound effect on every nation, even those untouched by a single bomb - put simply, they're not thinking straight - in the absolute confusion that will exist for a good period after the attack, the risk of the new Argentinian government chancing what they think will be a bloodless takeover (hell, they'll market it as a 'rescue' for the stranded British there) in order to unite the people behind it in tough times - sure, the defeat in the Malvinas left a bitter taste and killed the Junta, but this only makes the new government want it more, if you get what I mean. It would only be a bad decision in so much as 1982 was a bad move - one has to get inside the weird stuff going on during Armageddon. As mentioned above, if this does happen, things might get a bit complex.
I assume Aldershot and Aldermaston were hit? And RAF Northwood and Uxbridge?
If so then you've wiped out where I am currently, and where my family was in 1984.
Sorry to be the bearer of bad news...
Astrodragon - thanks for the comment - there were definitely a few duds amongst the hits on the UK (although given the amount of megatons falling per square mile this mostly means less overkill) and quite a few misses - only a few Soviet missiles hit their targets dead on - not that it matters in most cases, although this may come to be important later on.
The biggest effect on the mainland will come from the fact that CHANTICLEER (which the DPM ended up in, despite the fear the Sovs knew about it) survives due to a bad miss from a big bomb meant to ground burst it - to be candid, the DPM was gambling on this happening - after all, it would take almost a direct hit to turn the occupants of the bunker into soup, and there were few other places available for the DPM and staff to hide (more cynically, he is expendable - there are other nuclear deputies and military leaders hidden around the place - even at sea, as we have seen)
A more obvious effect of the dud nukes comes when looking at more isolated NATO targets around the world (which will be discussed in more detail once communications are restored) - here, a failed nuke is the difference between life and death, rather than the difference between roasting on gas mark four rather than gas mark three.
