I haven't noticed the No-Divs notam since those few days of widespread fog which also affected MAN a month or so ago. It was surely our weather that was an important factor.
But of course, we don't really know what refusals there have been when the notam is not showing. Watching flights divert elsewhere when they might have been expected to come to MAN doesn't mean they were turned away. I guess only the guys in airport ops., with the airlines involved or possibly ATC might know the full picture.
Good points Curious Pax.