1805, I just dont think you are looking at the true context of the time 1970-1989. There are many interesting questions and what ifs and many errors made by the MOD but you cant get away from basic facts.
There was a cold war raging, we were spending 4%of GDP even at a time of economic chaos, supporting armed forces of 320,000 plus much bigger reserves. Equipment dating from the 1950' and 1960's across all three services was becoming obsolete (eg Sea Cat as you point out was awfull) Look at all three services on this cold war footing.
Just some of the major procurement in the 1970/80 timeframe include MRCA leading to Tornado 220/165 IDS/ADV purchased, dire need for AEW after the Nimrod AEW disaster. Challenger and Warrior for the army. The Navy had a need to replace a steam driven fleet and NATO was faced with a new generation of quieter soviet submarines being pumped out at an alarming rate, the cold facts are that without major resupply from the USA across the Atlantic NATO could not hold out for long. The entire focus of the RN and therefore what ships that you think we should have built, must be seen in that context.
The focus is the North Atlantic, if the Soviet Navy wins that battle and shuts the Atlantic, we are all red. There are airbases in Iceland, UK and Norway so our hyperthetical navy has some degree of aircover but we know thats far from perfect. There was an urgent need for TAS to be deployed, hence the Type 22, hence the expensive refits on 6 Leanders I think. Yes Sea Wolf at the time ws very big and expensive but Sea Cat needed to be replaced, Sea Wolf worked, and still works. Area defence was actually pretty well covered in that N Atlantic context, there were to be 14 Type 42, Bristol and Sea Dart on the Invincibles, so 18 ships to cope with a threat of long range bombers and anti ship cruise missiles that came in at altitude , not sea skimmers.
The decision to bin the carriers had already been made as wrong as it was but that was the way it was. Harrier was added to protect the ASW group from Soviet MPAs and bombers, UK Industry in the 1970s was said to be able to sustain 20 nuclear boats including the deterrent, and at somestage I think we deployed 14SSN, we also needed to replace the Oberons, and had to fund the Upholders, and had the cold war not ended the production run of the Upholders was potentially as big as 17 boats, because we just couldnt get enough SSNs to sea for the Cold War requirement. The submarine fleet into the 1990's without the cold war ending would have been well over 30 modern SSN/SSKs, the surface fleet would have had 18 Sea dart ships, and specialised ASW fleet of the remaining Leanders and Type 22 and its cheaper cousin the T23 in the pipeline. All that at a time with dozens of competing procurement programmes. Within that were different types of ships likely or even needed?, would we need a Type 82 with a type 23 powerplant? dont forget ships last 30 years, we already had hulls in the water.
Faced with the N Atlantic task, what use do you really think a fleet of 80m Spanish Corvettes with no helicopter facilities would have been to the RN, how would those ships have fared in the N Atlantic when you consider the much bigger Type 23 was designed to be worn out in that environment after only 18 years, and it was specifically designed to drag a TAS through the foul N Atlantic seas. The Descubierta type ship would have been bugger all use to the RN mission, bugger all use in the contect of the "war" being fought, fine for Spains mission as part of Nato, not ours, so even if it may have fared OK in Falkland Sound, it would never be realistic. I dont know why you are fascinated with these ships?
Prior to the collapse of the soviet union, I dont think the Navy did badly for the job it was asked to do by the Politicians. Post Soviet Union we saw massive cuts in Options for Change, yet we still had a series of specialised ships with plenty of life left in them, hence I dont think getting something akin to a Burke was really an option in the 1990's and building a new fleet of destroyer with VL Area Defence SAMs may not have crept passed the bean counters.
The pros and cons of dragging a 1960s era liquid fuelled ramjet into the 2000's has already been debated, maybe the UK should have designed our new missile but it would be rocket powered and not called sea dart. Sea Dart has gone as a concept, but UK Industry could have built something but I suspect that would have been done at a huge financial loss and would have few buyers lining up today.
