I do not believe this is the time or place to see a RAF SAR vs Civvie SAR argument be renewed. Pointing out the differences in equipment and procedures is fine....but what is being discussed is how an experienced Crew in a well equipped aircraft came into contact with terrain.
the valid point about procedures in this case (without reopening the debate) is that instead of having a dedicated radar operator who controls the letdown (and can have a FLIR picture on one screen and the radar on another) while the copilot concentrates on monitoring the pilot, the AP and the nav - you have instead the co-pilot doing everything whilst the two very capable guys in the back can only interject if they see something on their screens they don't like.
Because in civilian SAR, the rearcrew are not flightcrew (no licences) they are not allowed to be responsible for the navigation of the aircraft - this is such a waste of crew resources simply because civil aviation regards anyone not in the cockpit as cabin crew.
Those rearcrew who are ex-mil will probably still try to take as much of an active part in any letdown because that is the way they are wired - those who have spent their time as 'cabin crew' are perhaps used to being 'ignored' which might explain why the request for heading change was not made more forcefully.