Yes, particularly on and around the Falklands themselves. The single largest project was the construction of RAF Mount Pleasant which is now the linchpin of the Islands defenses. It is usually occupied by four Eurofighter Typhoons, a TriStar tanker, a C-130 or two, and several Sea King helicopters. The base also houses small British Army units, usually a company and supply and engineering personnel. A Rapier Anti-Air missile battery is also deployed around the base.
There is also a significantly beefed up naval presence, partially due to the perception that the proposed withdrawal of the icebreaker HMS Endurance emboldened Argentina to start the conflict. The Royal Navy now deploys at least one surface combatant to the Islands at all times, usually a Type 23 Frigate, Type 42 Destroyer, or Type 45 Destroyer. The Royal Navy also keeps a River class patrol vessel on station at all times, and an Icebreaker for 6 months out of the year.
In regards to the rest of the armed forces, RAF Ascension Island remained in use after the war to provide a staging point if needed. Major restructuring wasn't really in the cards immediately after the conflict though, because of the looming threat of the Soviet Union. The Cold War posture of the British military was not expeditionary in nature. The Navy focused on anti-submarine warfare, as evidenced by the Invincible class carriers they chose to build, which were designed to operate mostly helicopter forces to hunt subs (which made things difficult during the Falklands War, when only Harrier jump jets could be used). The British Army also remained mostly a armored/heavy infantry force with an emphasis on fighting the Soviets in Germany. Since the end of the Cold War however, the British Army (as well as most Western militaries) has undergone significant reform, moving towards a focus on expeditionary warfare. I'm starting to skirt the 20 year rule, but examples of this new focus include the creation of the [Joint Rapid Reaction Force Concept](http://en.wikipedia.org/wiki/Joint_Rapid_Reaction_Force_(United_Kingdom), as well as in the design of their new Queen Elizabeth class carriers, which seem to be much more optimized for expeditionary, rather than local anti-sub, warfare. It's difficult to tell which of these later reforms are driven directly by the Falklands War, and which are simply common sense steps taken with the decline of the USSR, but it seems likely that the UK has taken what lessons it learned from the conflict to aid in the restructuring of it's armed forces.
The Ministry of Defence published Board of Inquiry reports into the loss of ships during the Falklands war, e.g. the Type 42 Destroyers HMS Sheffield and HMS Coventry.
The reports contain many recommendations that resulted in changes, though generally relatively minor (e.g. system updates, or changes to drills, training and procedures). Smoke was a major problem, especially for Sheffield, lost to an Exocet missile even though the warhead did not explode due to the subsequent fire, so there was a major effort to reduce flammable/toxic materials such as foam in mattresses and upholstery, and PVC cable insulation (Historical Aspects of Fires, after Impact, in Vehicles of War).
The loss of Sheffield and Atlantic Conveyer to Exocets also emphasised the danger of sea-skimming missiles, resulting in the rapid procurement of the Phalanx Close-In Weapon System (CIWS) for the Invincible class carriers, later upgraded to Goalkeeper, with the Phalanx units fitted to Type 42 destroyers. The Batch 3 Type 22 frigates ordered after the conflict were also fitted with Goalkeeper CIWS (SHORT RANGE AA GUN SYSTEMS OF THE ROYAL NAVY).