Ting! well looks like the penny finally dropped

So I read a few more articles and all of them refer to a plane of focus. So here is my new (and hopefully correct) understanding. The lens is shaped such that the focus of an image on the sensor or film is done for a plane parallel to the plane of the receptor. Thus the focusing distance indicated by the lens is the perpendicular distances between the two planes. See, that was my problem - I always thought that things would be in focus on an arc whose radius was the focusing distance. So in that case F&R would have worked - and it did for me from '67 till 2000 as most of my outputs were either contact print of 120 film or 5 by 3 or 6 by 4 prints.
Neuro, thanks for persisting

Others, thanks for the inputs.
So I had better learn how to do back button focus and selecting the appropriate AF point...