Falklands era question

Hope this is the right place to pose a question that has been troubling me for a few weeks now.

I have recently acquired a copy of Scale Aircraft Modelling, July 2002.
The Aircraft In Detail feature (in which I was interested) was on the Falklands Air War, and there are a few paragraphs about the presence of Soviet naval spy vessels shadowing the fleet on the voyage south.
It states that they were determined to observe the Task Force and that maybe one vessel got a bit too close.
The gist of this story is that a periscope was sighted by a helicopter from HMS Hermes and, since the location of the Argentine submarine fleet was unknown and the British fleet was on a war footing, this unknown submarine was attacked and was regarded as sunk.
It carries on that post-war records now indicate that it was not an Argentine sub at all but was more likely to have been a Russian sub which had ignored the international warnings.
Has anyone heard this before?
A quick flick through my favourite reference book ‘Falklands – The Air War’ by Messer’s Burden, Draper, Rough, Smith, and Wilton, brings up the story of 826 Naval Air Squadron and the hunt for the Argentine submarine ARA San Luis.
Apparently three Sea Kings were detached on 1/5/82 to carry out an ASW search with the frigates ‘Brilliant’ and ‘Yarmouth’ for a submarine in an area to the north east of Port Stanley, about 180miles from HMS Hermes. Each carried a spare crew of 4 and each refuelled in flight from the frigates. XZ577 established a then world record for its 10 hour 20 minute operational flight whilst on a mission, such was the determination to track the sub down. 6 Mk11 depth charges and 2 Mk46 torpedoes were dropped before the helicopters returned to Hermes sometime after dark.
Argentine submarine ARA San Luis was on patrol, but off to the north of the Falklands, and is believed to have made at least 4 torpedo attacks on the fleet, on 1/5, 4/5, 5/5, and 10/5, with subsequent claims to have closed to within 1,400 yards of one of the frigates. It did survive the war.

In addition:- many years ago I had the fortune (or misfortune, maybe) to ‘chat’ with a gentleman (and I say chat but he gave the impression of not wanting to talk even though he approached me – and even then it cost me a drink!) who claimed to have been on duty when a Fleet Air Arm Phantom ‘splashed’ a Tupolev Bear in the early 70s. He said it was coming toward the Scottish coast, the QRA bird was launched and then it was all over. Apart from the fact that he said it was a FAA Phantom (and I queried that because I assumed that QRA was pure RAF thing) he made it all sound so convincing but without telling where the Phantom took off from, where this incident was supposed to have taken place, nor a whole host of other details which I could only think of asking him about well afterwards (I will admit that we had both had a drink, but he’d had several more for each one of mine). Talking later to a Lightning pilot from about the same period makes me think that something did happen (he went through the motions of repeating the story as though in disbelief but throwing in corroborating detail that I hadn’t yet mentioned to him, like the wreckage apparently coming down 4 miles offshore), and when another enthusiast questioned this incident with me quite out of the blue when a Bear visited IAT Fairford a few years back I felt a shudder down my spine.
I am totally prepared to believe that both these incidents are complete rubbish, urban myths to be laughed about in the same fashion as those stories of crates of brand new Spitfires being hidden in old railway tunnels at the end of WWII, but where there is smoke there might be fire – or someone with a box of matches and a sly grin.
Unless, of course, anyone knows different?

Flood.