Ok, I'm going to answer my own questions here.
I just rang Auto Barn Lawton (they also build race motors) and he said that they are out of business.
He has fitted 2 sets of JP engineering gears with no problems.
He also has a set on the shelf.
So I'm all sorted.
BTW they also keep Gray motor engine enamel, water pumps and other parts.
Talk to Rob. Awesome to deal with. Unlike Repco!
Cheers
Jeff