Apart from northerly winds, the circle onto 36 will be used when 36 is used for departure. In these cases the approach will normally be 'sanitised' for the departure. It will be a less common event that there will be a conflict betweeen circling g/a's and 18 ILS's. Still a possibility, though, and I too am interested PP in the reply to your company.
I would have thought that. in view of the procedure track, there was time in the event of a g/a from the 18 ILS to clear the approach?