Lemurian,
I think there were two separate N-P approach procedures, both using VDF.
The VDF approach, part of the UK PPL IMC Rating syllabus when I did it and as you say very good for sharpening up one's situational awareness in cloud, was as you say the total responsibility of the pilot; all the Controller had to do was provide QDMs when requested, and authorise the various stages.
The detail you provided brings it all back!
But the QGH procedure, in which the Controller took charge, also existed as an alternative, if the Controller was suitably qualified. I have a feeling that it was used primarily by the RAF, although I did a few at civilian airfields, largely to provide the Controller with some practice. They took an interminable time in a light aircraft, and getting the wind/drift calculation right was a major factor for success; in a fast jet they must have been much more exciting for all concerned, with so much less time to work it all out.