First point to make: this is not a movie, not even a TV movie. It's a British TV drama, and more like a stage play, very static and almost entirely people sitting talking. Janet Suzman is a classically trained stage actor in the great British tradition. She was once Oscar-nominated and is reasonably reliable but her approach is more mannered than method, and the cast generally follow this, making the whole thing feel a bit stuffy.
The '70s director tries to be avant-garde: there's a lot of hopping around in time, showing Nightingale as a girl, an old woman and at various stages of her career; actors deliver monologues to camera, and so on. This is mostly just confusing. There's even a strand with a modern (well 70's) student writing a paper on Nightingale. At one point this student describes her life as 'boring' and, apart from the confused treatment, this is the main problem here. Nightingale wasn't a very sympathetic character, nothing dramatic ever happens and, unless the subject matter itself grips you, boring is how you may find it.
However it sticks fairly well to the facts of this life. Nightingale was a campaigner, who achieved great things through influencing others, rather than her own actions. Through various politicians she had an important role in revolutionising the medical profession and establishing the position and status of nurses. If you don't know a lot about this subject, you may find this play-movie quite interesting.
