The decision to invade the Falklands had very little to do with the capabilities of the RN and everything to do with internal Argentinian economic and social stresses.
MM
I would say it was a combination of both. My father was a CPO Mech working in NATEC on the SHAR at the time. He told me that in 1980'ish the Argentine Navy sent a delegation to look at SHAR wrt possibly ordering it. They came away saying it was a toy. Suffice to say - they didn't call it that 2 years later.