It is very rare that a movie, especially a BBC sponsored movie, is actually better than the book. This is.
Ford Maddox Ford tried to express the sheer Unspeakable HORROR of how a generation of young men were slaughtered, en mass, because of the complete moral and intellectual break down of an entire class of British (German/French) ruling class. But, perhaps, Ford was just too close to this horrendous, unintelligible disaster. One of his characters, Ms. Wannop's brother, as depicted in Stoppards competent script, probably best exemplifies Ford's hysterical, over wrought, desperate attempt to come to grips with the First World War.
Stoppard leaves out the entire fourth book and reduces the remaining three to a few telling moments to try to salvage a coherent narrative. He does a creditable job of it. With what is left, the script offers the actors (who are all excellent) room to make what is possible from Ford's book(s) - The more recently celebrated "Birdsong", does it better. (Though the BBC movie of it is execrable) - With the advantage of 60 odd years reflection. "Behind The Lines" (Books and movie) does it even better.
Why bother? Well, we, in the USA, are just coming out of two major military engagements. We the public and they the military can learn a lot from watching this and the other mentioned movies.
The sad tragedy never ends...