I find it helps to think of the books having an internal timeline (when things happen relative to other events in the books) and an external timeline (when things happen relative to real events).
So in relative time, Chudleigh Hold takes place three years before Lavender, when Gillian is a new girl (she's twelve in Chudleigh Hold, and fifteen in Lavender).
In external time, you can't make the two books fit, because the war would have to be in progress in Chudleigh Hold. In general, EBD wrote the books in the time period of the time, with WWII forcing explicit references to external events. Jo to the Rescue was published in 1945, for example, and was the last book that was set during the war - Mystery, Tom and Rosalie take place when the war should have still been in full force, but there's no mention of it.
EJO's books are even more striking for this. The internal chronology (unlike EBD's) is very consistent, but two books set only a few years apart in story-time have one with telegrams and horse drawn buggies, and the next with telephones and
cars, as one was written in 1909 and the other in 1957.
Ring the bells that still can ring; Forget your perfect offering
There is a crack in everything; That's how the light gets in
Anthem: Leonard Cohen