Reasons #Daventry is a cartographic hoax:
Everywhere else has Anglo-Saxon place name suffixes: Rug-by, Sout-ham, Bar-by, Kil-by, Ash-by, Buck-by, Cates-by, Mars-ton, Hey-ford, Wat-ford, Dod-ford, Staver-ton, et al..
Daventry's entry in the O.S. gazetteer was clearly added by a bloke named David. But xe didn't want to be too obvious that it was "Dave's Entry" in the list, made as a copyright trap.
Ha ha! Funny joke, Dave!