Thanks for the tip Pete, that would be great if you could put a picture up for me.
The thought occurs that if this type of car is being brought in as a front cut then there are probably a few spare heater controllers floating around. It probably isn't the kind of thing that fails just because a car gets a new engine.
We got an original controller off a Crown at a local wreckers on Friday, but it will be going back as it doesn't shut the water off. We have a temporary solution of putting the JZX90 unit onto the heater lines, which allows us to operate the tap in the engine bay, but I am not keen to install an extra cable into the cabin. So I really want to replace the old one with a similar enough unit to be able to use the existing controls.
We are near Gympie, which is about 180km north of Brisbane on the main Highway.