I'm also playing catch-up due to a rare reading lull in which I began several books hoping for the book riveting enough to capture my attention. Having now completed three of them (had to clear the deck), I am finally at 12% of Testament of Youth. I love the way she writes and her account of her life in pre-war England.
Although I vowed to plow straight through in order to catch up quickly, it is the kind of book that inspires exploration and I've appreciated Bookworm_Girl's links. Here is another link I've enjoyed, especially for the audio of Vera's and Roland's letters to each other:
Violets from the Trenches.