Sadly, after the enjoyable second book this third one was again a disappointment, like the first book.
Couldn't get behind Di's motives, first trying to keep things casual, and then falling in love head over heals. From "I want to get married in half a year" to "Let's get married yesterday" within a day, sounded quite mentally unstable to me. (I get there's a war and it was different from today back then, with Ted and Millie I could understand it, but Freddy and Di didn't convince me.)
Also, Johanna is worrying one evening about her mother-in-law's mental health, and the next time it's her perspective the concerns are just dismissed without another explanation.
Generally, the things that bothered me with the first book bothered me again with this one.