The best place to start the next Oakhaven novel would be with the sergeant and his wife worrying about where he might be sent. They could be preparing a kind of dinner party for the nobs in the village, Mrs Boniface, the doctor, Elaine and Colonel Cunninghame and discussing the future. That would be a reminder of all the plots as they run through the guest list.  Their main concern is of course their children, the girl is near her final exams and they don't want her moved. Maybe they plan to ask if the wife and the children can stay and run the big house while the sergeant is away.

http://www.amazon.co.uk/Colonels-Ducks-Oakhaven-Best-Plans-ebook/dp/B00XPHOMAE/ref=sr_1_6?s=digital-text&ie=UTF8&qid=1452518897&sr=1-6