Let's see....
Following the Faulklands the RN frontline fleet consisted of 3 carriers, one centaur and two Invincibles with a 3rd under construction. 8 type 42,s with 3 under construction. 4 county class destroyers (1 out of action following an Exocet hit). 6 type 21's, 8 Type 22's with 4 under construction ( 2 of which were named Sheffeild and Coventry as replacements). A number of type 12l Leander's and the Type 82 Bristol. 4 SSN's of the Churchill or Valliant class, 6 Swiftsure class SSN's and 4 Resolution class SSBN.
So in my line of events. Following the Falklands the Royal Navy is to increase in size and repair the damage done by the politicians in the 70's.
The carrier fleet was totally rethought. 4 CVN Class carriers were built between 1987 and 1991.
The centaur class carrier Hermes is sold.
The invincibles are sold off to Australia, Canada and New Zealand.
The 11 type 42's would be retained as these were relatively new 1978-85
The single type 82 would probably soldier on into the early 90's until a newer fleet cruiser (fulfilling a similar role to the American Aegis cruiser in the carrier defence role) could replace a non standard vessel (My first design)
The County Class destroyers would be disposed of soon after the war, they would be replaced by 4 to 6 new ships probably an interim design before the fleet cruiser, a modified type 42.
The Type 12l Leander's would be quickly phased out, built in the 60's they were beginning to wear out, they would be replaced by a new general purpose Frigate (My second Design)
The type 21's, would be rapidly disposed of and replaced to by a new general purpose Frigate.
The type 22's being relatively new 1978-89 would be retained with possibly the batch 3 order increased by 2 hulls to help fill a gap created by the early disposal of the leander and amazon class.
The Churchill and Valliant class SSN's would give way to 7 Trafalgar class SSN's in 1983-91
The 6 Swifsure class would be retained again these were relatively new 1976-80.
The Resolution class would have been in the process of being replaced by the Vanguards between 1992-99. Dependent on hull condition and if replacing the old reactors is possible maybe converted to SSCM,s. (Rotary Tomahawk launchers installed in place of the Polaris missiles).
Fleet Cruisers (My first design) 8 hulls to replace the type 82, County class and Tiger Class, provide air defence for carrier battle groups and flagship duties, to be built 1987-92
General Purpose Frigate (My second design) upto 25 hulls to replace the Leander, Amazon an batch 1 type 22's, to be built 1985-95.
4 CVN's designed and built within 10 years? That seems more than a little optimistic to me.