My word,
what a find Lalaith! The psychologists would have a field day!
A few thoughts off the top of my head.
Social position in those days often brought insecurity with it, doubly so in a place such as Oxford I should imagine. Was Edith perhaps frightened in a way of 'letting down' her husband with his highly prestigious position as Professor? No doubt the dons were a difficult bunch to interact with socially, even for a respectable married woman. Seems very sad as Lalaith says, but 30s Britain was class-concious to an extreme, most intimidating no doubt.
Still there are worrying tones of Lobelia.
I love the Prof's colourful waistcoats! I hope he replaced the brass buttons with big gold ones like Bilbo's after the books became successful.
I wonder if Adda was stereotypically Icelandic - blonde hair, blue eyes etc, no wonder Edith kept a close eye! Was Adda proto-Eowyn perhaps??