I am not familiar with any tracking system in the UK SAR S-92. However, all offshore (civilian) helicopters in the Norwegian North Sea sector are required by the CAAN regulations to have the M-ADS working. (M-ADS = Modified Automatic Dependent Surveillance System)
It is a very nice system from a pilot's point of view. You turn it on after startup and then more or less forget it. It automatically transmits Flight Management System data like position, altitude, speed, rate of descent or climb, weather data etc. etc using SATCOM.
It is also connected to the transponder, and should you select 7700 or the other emergency codes, ATC wil notice immediately. The rate of transmissions are selected by ATC, normally every 30 seconds, but will be increased during certain conditions like high rate of descent etc.
These data are received by ATC and super-imposed on their radar screen. If you are in or out of radar contact - no difference. They will see you like any other aircraft - anywhere as long as you have SATCOM contact. I will not get into the finer points of ATC regulations on separation etc, but the main point is they see you all the time, even when parked on a helideck offshore. Theoretically, the ATC in Stavanger can see a M-ADS equipped helicopter anywhere in the world. I believe that the Rescue Coordination Centers in Stavanger and Bodoe now have access to the same data in realtime.
As for pilots, it is great. You get direct routings most of the time, saving time and gas, and you don't need to send position reports every 15 minutes or so. In the Norwegian sector, it meant that the radio chatter was decreased, time to read the newspaper, eat the onboard lunch etc.
ATC takes care of separation from other traffic (as long as they can see it, mind you)
Sadly, the boxes are not produced anymore due to low demand, the UK of course did want to touch it as it was not invented there. My guess is that it will be replaced with ADS-B (B=broadcast) in the future. BTW M-ADS is a ADS-C system where the C stands for contract. You establish a connection (contract) between your aircraft and the receiver, in Norway the ATC.
Why wasn' a similar system put on the Air France 330?? They have ACARS, but no nav data.