This entire episode is a literal example of a "drawing room drama."
It's interesting to see how Roger's attitude towards Collinwood, and indeed what it means to BE a Collins, evolves over time. Here he's ready to throw the old "white elephant" away for some bloody lucre, but by the time Barnabas arrives on the scene and, indeed, in all the time thereafter, Roger is a full-on snob about both the place and the family name.