I had all of that - Kenlow 16", two settings X-Eng thermoswitch in bottom hose, warning light and override switch but the temp gauge still fluctuated and got hot enough to switch the fans on in slow stop start traffic. Mind you a single fan may not have been enough but it came with the Landy.
With the viscous it gets to running temp and stays there - within a few degrees - whether I'm cruising, in traffic or belting it along.
Matter of choice really, the viscous v electric fan debate is endless (but LR did fit them as standard for some reason).
Mine came fitted as well...but the 101 is a whole lot different engine fit...came with the fan shroud and viscous fan lying in the back though...