Ad so here is a finished item. Ready to paint? Well, the edges need cleaning up and the plastic could be smoother...
But it does swing round and alter in elevation like the original.
Yet another working part!
These are the fittings which define this boat, so it's worth rolling out the carpet a bit. I splashed out on a couple of inches of brass tubing!!
Back to the trusty copper wire. A length of the insulation is left on to provide the handle, and the wire is then bent as shown.
Looking at a proper Fire Monitor, I note they have a conical end unit. I don't know what it does - something for mixing the foam, I imagine. But I do know that it looks exactly like the end of a biro cap....
Find a bit of plastic and push it through the top brass tube. I had to glue two bits of polystyrene sprue together to get a decent diameter, and file it roughly cylindrical. Pushing it through did the rest.
Then drill a couple of small holes through the plastic, either side of the brass tube, as shown.