To continue from "Park Brake 1" here are some additional photos of the valve mounted and the 4" spring - this is fitted so that if the park brake cable becomes disconnected the spring will force the valve open - so fail open.
Roll forward to March 2011 and when I fitted the park barke cable support hardware (HW WIRE NUT KIT) you can see that it interferes with the Left AN fitting.
Solution: I bought an AN823-4D 45 degree elbow and made a new pipe.