To mount it back at the top, all you
have to do is barely bend the factory
bracket. It looks fine (like it belongs)
when you are done.

If you leave it unmounted can it cause the engine light to come on.

I bent the bracket for mine.

It would seem from the photo, that UK spec cars get their knock sensor on the opposite side of the engine bay.

Figures!
You guys also put your stearing wheels on the wrong side and drive on the wrong side of the road. wink.gif