Having been part of the team that set up one of the RAF's first helicopter sim. training programmes, I was pleased to hear feedback from one of our pilots who stated that he was of the opinion his life was saved by guidance and training given to him regarding T/R malfunctions.
His aircraft suffered a tail rotor control failure over the sea (limited tail rotor power). He managed to spiral down and safely ditch the aircraft, which was later recovered. He said that without the training he would probably have chopped the engines, which would have been a big mistake; things would undoubtably have gone very badly wrong.
I also know of another pilot (of a non RAF Puma, not given our training) who suffered a tail rotor drive failure in the 140 kt cruise. He initially tried to slow down without chopping the engines but it began to go wrong so he accelerated back to 140 kts, flew back to an airfield and carried out a running landing at that speed. He apparently got away with it, too!