On 18 November 1987, a memorial plaque was placed on a wall along the walking path to the Three Sisters, close to the Echo Point Information Centre. It was inscribed in honour of the late Sergeant First Class A. E. ‘Ernie” Sanderson. As leader of the Police Rescue Squad, he was involved in scores of rescues. His leadership was an inspiration to the other members of the “mercy squad.” They carried out rescue operations equipped with only ropes, hand torches, and stretchers which they had to haul or carry on foot up to tops of the cliffs. During that period, there was no assistance from helicopters.
The plaque was erected in recognition of his services to the community. Sergeant First Class Sanderson retired from the police force, aged 60, on November 9, 1978, after 31 years service.

I went looking for the plaque but couldn’t find it.  It must have been removed when the Echo Point precinct was rebuilt.  It’s difficult to say what might have happened to it, as the management of the area has shifted between National Parks and Blue Mountains Council.  I was told to ask National Parks what they did with it, but there’s probably nobody around now who would remember.

UPDATE: following my post on the Facebook page, Pearl Cusack went to look for it and found it above the toilets.  Here it is:

The text reads:

SEARCH AND RESCUE SQUAD BLUE MOUNTAINS
THIS PLAQUE WAS ERECTED TO PERPETUATE THE MEMORY OF 
SERGEANT 1ST CLASS A.E. (ERNIE) SANDERSON 
(1918-1985)
IN RECOGNITION OF HIS SERVICES TO THE COMMUNITY
THROUGH HIS WORK IN THE ESTABLISHMENT AND LEADERSHIP OF THE BLUE MOUNTAINS POLICE SEARCH AND RESCUE SQUAD. HE RETIRED FROM THE NEW SOUTH WALES POLICE FORCE ON 9TH NOVEMBER 1978 AFTER MORE THAN 31 YEARS` SERVICE