yeah, but 22 SAS does have boat troops, as well as Mountain, mobility and Air. although, of course, Air Troop is guys like Sparrowhawk - paratroopers.
from wikipedia:
Air troop
Air Troop personnel specialise in airborne insertion from fixed wing and rotary wing aircraft. Leaving the aircraft at high altitude personnel are capable of delivering personnel and equipment into the deep battlespace far beyond the forward edge of battle area in support of their ISTAR or offensive operations.
Personnel are trained in three principal forms of parachute infiltration; Basic static line, High Altitude, Low Opening (HALO) and High Altitude, High Opening (HAHO). HALO insertions involve a long free fall followed by canopy opening at low level, about 2,000 feet (600 m), leaving the operator exposed to detection and fire for the minimum possible period. The aircraft must overfly in the vicinity of the Drop Zone to effect delivery, risking a compromise to the mission should it be detected. HAHO insertions allow the aircraft to deliver the operators from a significantly greater range from the Drop Zone, thus reducing risk of mission compromise. Operators leave the aircraft and immediately deploy a canopy which allows a long glide over great distance. To avoid hypoxia, the parachutists are provided with an oxygen supply to survive the depleted air at high altitude and warm clothing protects from the extreme environmental conditions.
[edit] Boat troop
Boat Troop personnel specialise in water-borne insertion techniques. Personnel are trained in diving using Open and Closed Circuit breathing systems, sub-surface navigation skills, approaching the shore or vessels underway and the delivery of maritime demolition charges. Much of this training is undertaken with the Special Boat Service.
One of the main forms of transportation is the Klepper canoe. The first SAS folding boats were designed during World War II for use by Commandos, based on existing designs. The German Klepper has been in service since the 1960s. Other transportation methods include the Gemini inflatable, used primarily for sending small groups of soldiers onto a shore undetected, and the fibreglass hulled Rigid Raiders - fast patrol boats which are larger and can carry more personnel or cargo ashore. Entry to the water is also achieved from rotary wing aircraft and by parachute drop. In case of the former, the helicopter hovers around 50 feet (15 m) above the water and personnel simply jump out. Airborne entry to the water carries a significant risk to equipment with weapons and other equipment sealed using a dry bag.
Deployment from submarines is also taught. Submarine egress bears a high risk given the effect of pressure at depth (nitrogen narcosis and oxygen toxicity), the cold, and the risks inherent in the use of mechanical breathing aids while underwater.[9]
[edit] Mobility troop
Mobility Troop personnel specialise in vehicle insertion techniques, similar to those of the Long Range Desert Group of the Second World War and allows a more sustainable patrol in the medium to deep battlespace but create logistical and force protection challenges.
Personnel are required to gain skills in vehicle maintenance across the range of vehicles used by the Regiment, particularly whilst on patrol with limited opportunity for combat support. Vehicles include the Jackal (MWMIK), Land Rovers, Supacat HMT[10], Honda 350 cc Quad Bike, CRF450X, and the Honda 250 cc motorbike[citation needed].
[edit] Mountain troops
Mountain troops' personnel specialise in the conduct of operations at high altitude and in mountainous terrain, requiring advanced skills in climbing, ice climbing, skiing and cold weather survival. Training is conducted in deserts and mountain ranges around the world. Those members that show particular aptitude are seconded to the German Army where they undertake the 18-month long Alpine Guides course in Bavaria. A number of members from the mountain troops have participated in major military and civilian expeditions to some of the world's highest peaks although this has not been without loss[11].
So Beaver, Barracuda and Stakeout would all fit as Boat Troop, Sparrowhawk as Air Troop and Stalker as Mobility. Eagle and Quickfire would be Air or CRW troops. Only Hunter doesn't fit, since he drives a tank.