Milestone.
I've finished overhauling the backbox and its back in the head 

The ball count unit needed a new spring kit.
The number match unit (and in this game the dealer unit) also needed a new spring kit.
The step up coil was also stuffed and the tip of the plunger mushroomed (coil stop was R.S) .
This is the 1st mushroomed plunger tip I've come across.
Basically this mech didn't work . It does now .   

So I reckon I'm now 75% finished on this machine.