Wifi automatically turns on persistently, despite configuration

I am using a Sony Xperia L (C2104) with Android 4.2.2 (Build number 15.3.A.1.17). I can only find one setting that would turn on Wi-Fi automatically, and it is the "Location-based Wi-Fi" setting in the Power Management settings category. Of course, I have disabled this option, but I frequently find my Wi-Fi on. How can I fix this?