My wife and I simply echo the earlier comments - this is so superbly acted and filmed that we immediately wanted to watch it all again. Dame Wendy Hiller shows acting craft at its finest, commanding the camera by her force of personality and subtleness of every facial expression and movement. All the supporting roles are also outstanding. Somehow the film seems to enfold you in the life of the woman who is given so little time to grasp at a life she wished she might have had.
Good news for all admirers: this film is now indeed out on DVD (2006 release), with an interesting lengthy text biography of the novel's author (Vita Sackville-West) among the special features.