You could just throw caution to the wind and pretend Greenfields never had one at all and make your own from scratch.
If there is a clear space above the deck spindle it would not be too hard.
There could be another spot, cant tell from the pics how things all work on one of them.
If the deck drive relies on tension over one of those big pulleys then to the deck them back to the engine over the other big pulley you could probably brake one of them.
Cheers, Bob.
