I don't remember anything like that as an O2 console. Looks like the engine from a Deltic locomotive.
We had what was known as the Interim system from the early 90s when I was at JATE through to 2011 because we could not get the modern system to work consistently. I am not sure what it was supposed to have been interim too.
Interim was a Mk10 bottle rigged with 7 outlets. 6 for the troopers and one for the despatcher. the orifices were metered to give a constant flow of 5 litres per minute. it was found the number of outlets was too many. I think it was cleared to feed only 4.
The low pressure gas fed into a long hose by way of an accumulator which was connected to the mask. We called this the snake and it was packed in a pouch. the trooper disconnected from the rig and opened the tap to his personal bottle. This was good for 25K. Only 18K at night. Funny story from a PJI about this who thought it was because the O2 concentration in air is lower at night! This was a guy who was training our finest!
We did have a small number of PHAOS American sets probably from 96/7. these were specifically for tandem and Tethered bundle. I think they may be out now. They were still in use in 2010 but restricted to 18K due to regulator issues. It had been 25K prior to a few incidents. I think the spams may have bragged about it being good for 35K but not in UK service.
The system R4H describes was known as AMOS which initially had two high pressure outlets feeding a Harrier regulator. (later a Jaguar 417) for aircrew including the loadmaster before we developed a special 100% O2 only regulator.
The parachutists system R4H tested in CL was connected to a Carleton console similar to PHAOS when on the aircraft for pre-breathing. He disconnected which automatically allowed his regulator and mask to be fed from a rather nice lightweight composite bottle at P-2
This never got into service. Meggitt developed the AMOS Mk2. I even see there is now a Mk3 but I have lost touch.
35K was tested but never got into service. We became quite risk averse. Many hours spent in the chambers at IAM and setting regulators upon B2 stands. The failure rate was very high in the early days. It was like a hair spring against a gossamer thin rubber diaphragm. fingers like pigs tits was quite a handicap. There was a time when we could only get 10 out of 150 regulators serviceable. Hence the retention of interim system. Still the contractor got his £squillion. Contracting for availability had not been invented.
I am sure things are all hunky dory these days.