Just finished Rennie Airth's "River Of Darkness" and I highly recommend it. Great post WW I in England feel. However, you might want avoid if you don't like serial killer books (as a rule, I don't, but this book held me riveted, and it's LONG too...).
I'm reading the sequel, "The Blood-Dimmed Tide", now. Much shroter. Set some 10-15 years later, very good for pre-WW II atmosphere in Britain *and* Germany. More serial killers, though and would definitely help to read in order...
There's a third out this summer called "The Dead of Winter" and I really think I'm going to have to look for it!