The Two Mrs. Abbotts is the third book in the Miss Buncle series, and while the title suggests it's about the former Miss Buncle and her niece-by-marriage, it is really not.
Of the two, we spend the most time with the younger Mrs. Abbott: Jerry. We see Barbara every now and again, but her story line is nothing substantial. Actually, none of the story lines are. There are just too many characters and too many plots going on that it's hard to keep it all straight.
This is a weird little book, because while it takes place during World War II, it's about nothing at all, really. There are certain characters that we see for a little while, and then they disappear never to be heard from again. And at the end of the book, there are a bunch of characters' stories still hanging there.
Unfortunately, the charm of this series dissipates with each book. If you like books set in the country during this time period, then this is probably your thing, but it just wasn't mine. If you liked the first book Miss Buncle, don't feel the need to continue because the two books after it are just pale imitations, sadly.