That's the one, Swan Knight. Thank you!
Barbara Leigh-Hunt as Cosima: it's all coming back now. I'm fairly sure that Jack Brymer was one of the players on the stairs and I think that was how he first met and became friends with Timothy West (who was probably Richter rather than von Bulow come to think of it). I may be making this bit up but I have a vague memory that they filmed the staircase bit on the ACTUAL staircase (omigod!
). But if that is impossible because the house was pulled down years before I'm more than ready to have that illusion shattered.