Was this not a government motion?
Why was it not (also) a confidence vote?
It was but not a confidence vote by definition.
The last time there was a motion of no confidence was apparently in 1979! A good few years before I was born!
Normally, the threat of a leadership vote of no confidence as in what happened to Thatcher (causing her to resign) and was threatened of Blair, Brown and Cameron to varying degrees can cause a leader to resign or stand for their position.