
I found these three novels by O. Douglas in a local secondhand books shop yesterday and I couldn't pass them by; "nice books about nice people" are too few in number, it seems to me, and from what I know of the author, that's a fair summing up of her work.
The House that is Our Own was first published in 1940, and it bears the following touching dedication to the author's brother, John Buchan, who died early that year:
"To you, J.B., who with little liking for mild domestic fiction, read patiently my works, blue-pencilling when you had to, praising when you could, encouraging always, I dedicate this story, which you are not here to read, of places you knew and loved."

I was interested to find this sticker inside the back cover of one of the other books - Binns was a well-known Edinburgh department store, now House of Fraser. That it sold books is news to me, but I suppose such shops did in those long-gone days.
Turning to the books' dust jackets (and these have plenty of period charm), a couple of short articles on the subject - here and here - may be of interest.
Edited to add: I've linked above to two very striking portraits of John Buchan; here is one of his sister herself, the family resemblance marked.