I take your point about locating the Indian Carrier(s) somewhere around Diego - where the air supply would probably also be more easily intercepted - But just as an aside, in Operation Atalanta I assume they were looking for little pirate vessels which I assume would be harder to spot than British supply planes? Also looking up the operation on Wiki, it does not look like they had much in the way of numbers for reconnaisance aircraft.
France has E-3F and Atlantique IIs off Djibouti looking for them, the US has their own AWACs, P-3s and drones as well as US carriers in the region. I was also referring to British convoys as well as the air bridge. Starting in the Western IOR, it is still like looking for a needle in a hay stack.
Let's take the two scenarios of an IN battlegroup positioned off Diego - firstly with a single Vikramaditya and then with a fully operational IAC. With supporting destroyers, frigates and corvettes covering the full range of ASW, Air and land attack. Plus Sukhois (and Raffales?) attacking from the mainland with refueling tankers. So can India in each of these scenarios ward of the Astutes and type 45s and attempt a landing with reasonable chance of success?
At the rate Vikrant is going, it will be questionable if the ship is fully worked up by the date. Since India gets to pick the time and place of aggression, I will go ahead and say both can be available if one plans for it long term. If you have two carrier battle groups then most of INs major surface combatants are going to be tied up as escorts. With the long range Spearfish torpedo, an Astute can shoot and kill you by the time you even know what is going on. With Russian sonars being the backbone of the search, I really don't see it making a difference. You need ultra sensitive towed LFAS sonars to catch Astute, something IN doesn't have. IN will be at the mercy of her torpedoes unless you get a lucky contact. Like modern torps, Spearfish doesn't start making alot of noise until it sneaks up on the target and goes full speed. Only hope your hydrophones pick up the swish of the torpedo tube and a swarm of Helixs to investigate. You may get one after a torp spread. You may or may not save your carrier as that is going to be the prime target. Lets say you lose one carrier, kill the one or two SSNs that launched on you and carry about your business.
You still have 16 MiG-29Ks and 6-8 Flankers that can get to the area on a regular basis around 3 IL-78s. Not all in air due to sortie generation issues. There should be one squadron of Rafale that France made available. Add on 6-8 combat Rafale's as others will act as tankers. It doesn't look bad against a dozen Typhoons. But then RAF could send a second squadron. 24 Typhoons could deal with that. Backed up by a Type 45 initially, then a few with the task force will make flying around the island a deadly proposition. IAF can attrite Typhoons with more Flankers, just have to do it in waves. But it can't afford to suffer major losses against Type 45s. A salvo of Brahmos isn't going to do the job. You can kill one with a concerted attack, but against 3 the power can't be brought strong enough. You need Scorpenes with Blackshark torpedoes to sink the RN. A Type 45s sonar is no match against them, but the Type 23s have new Thales 2087 LFAS and the Merlins have latest Thales dipping sonars. RN ASW is top of the line. But then against Scorpene accoustic reductions are top of the line too. With Blackshark long shot capability, you could do serious damage to their fleet. Don't expect to get away though.