Scottish aviation twin pioneer also has reverse swing. Still trying to find out why, probably something to do with the middle fin swinging the back end in the "wrong" direction after engine failure. Once its settles down everything happens between 75 and 80 knots. About right for a good seam bowler.
We should have chucked a few of them at the Aussies.....mind you 'm not sure it would clear the boundary on one....