Justin when I was looking for one of those, many years ago, it was nearly impossible to buy, however I had 2 made, from a place called Mc Knights Electrical and Motor Winders.
Although this place doesn't exist anymore, those were the places that were most helpful and knew what you wanted.
I know this is probably not much help at the moment, but one can get them, although it may take some time to find out where.
Leon
