Glueball,
the Circling Approach is supposed to be a visual maneuver, conducted in VMC
Not so. In Oz, "Visual Circling", as it is called, is not required to be flown in VMC but within the minimums of the chart, normally 4km vis. And given that VMC is only 5000m vis down low, even that is extremely dodgy if you are outside the circling area, which I can only assume you'd be if you were terpsing it. If there is a mountain just outside the 1.7nm circling area and it suddenly comes into view on the nose, you're probably going to go very very close to it, especially if you are looking over your (or the FOs) shoulder for the runway.