"isn't the true limitation of one's own GBAD assets measured against the compartive quality of the assumed opposition?"
Arguably yes. Considering the level of the threat to MPA, it could be easily argued that it isnt worth our while investing in a solution similar to Patriot. As yet, I'm not aware of any SEAD assets or ordanance that is or is not in the Argentine arsenal. I'd like to think though that should they acquire such weapons, however crude/outdated from anywhere that HMG would take a view on how such assets may tip the balance away from the defenders of the Islands - the radar sites are completely static and so far as I'm aware have never been able to defend themselves against any type of attack. Apart from Blowpipe Det's in the 80's, its been an open secret that these sites would be sacrificed and left to their own devices if the balloon went up.
"Are the Argentine forces in any position to exploit any 'weaknesses' in UK GBAD assets in the Falklnads given the complete lack of support said forces have experienced from their government over the last 29 years?"
As it stands at the moment, short of Arg Special Forces, I do not have any inside knowledge or access to classified info as to what HMG perceives the direct threat to MPA or the mountain sites to be. The short answer is "I sincerely hope not", although saying that they cannot now does not mean they never will be. I'm not sure I'd agree with you about complete lack of support. Under-resourced, under-financed in some respects, maybe. But complete lack of support I think might be pushing it.
"As a 'for instance' it is believed by many sources that the only ground attack a/c the Argentine military can muster in any numbers at the moment are some A4s and a small number of Pucura. Just how 'limited' would GBAD assets need to be in order to allow subsonic and short-legged a/c such as these to approach the Falklands?"
From my own recollection of MPA and FIADGE, I am not aware of any electronic warfare threat to GBAD or, as I said before, any SEAD capability that they may or may not have. Doesnt mean none exists or none is going to exist, should the Argentines acquire such platforms. The A4's and Pucara's are incidental. The keys to the whole piece revolve around the size and dispersal of the FI garrison (much reduced over the last 10-12 years or so), the resident naval presence (likewise) and the amount of Typhoons. Woodward's scenario was based on an incident or series of incidents at the edges of the FIPZ that would drag the airworthy Typhoons away from protecting MPA, long enough for an airborne commando assault to start taking the airfield. As soon as the first sets of wheels touch the tarmac, or the first sets of boots land on the ground, it is then too late. The Typhoons part in proceedings is then utterly redundant.
Is it possible to reach MPA by air without being spotted by the mountain sites? Hell yes. Always has been. Particularly if you're distracting attention elsewhere.
And, as I say, its not about now, its about four or five years hence. God knows what state GBAD will be in by then - I'm not aware of any other GBAD asset procurement programme to replace Rapier and other platforms - plus reduced army and air force manning, plus decreasing the amount of squadrons, plus more demand elsewhere on the Herc fleet and FSTA taking over from the VC10's, no LRMPA, last of the T42s gone - and however many SSGN's we've got, they cannot be everywhere. Likewise, SSN's. Good as they are, they still have vulnerabilities and if they're being chased over the southern oceans by Argentine Subs or ASW assets, they have to spend more time staying safe and less time being a threat to the Argies themselves. And, from a quickly executed prosecution of an airfield capture, they're somewhat superfluous.
The best way to recapture the Islands is not to lose them in the first place. And the only way we'll do that, if we are not going to make a sizeable presence there is to ensure we can reinforce quickly and effectively. That capability, plus the heavy reliance on Intel sources as opposed to a standing force to give you heads up warning and to deter agression is a rubber band I personally being stretched more and more thinly.