Now that the wiring is in I've been running the motor a bit. As you would. And I've started hearing noises. As you do. Ones that weren't there before.
Rob had come over and we spent a while trying to isolate the source of a rattle at the front of the engine. I had thought it was the idler pulley, but inspection and reassemble had made me think that it was OK. The next culprit was the recently attached, but original un-kitted water pump. It did seem to have a little coolant leaking out of the tell tale hole. I had had the pin hole repaired in my rebuilt pump, so off came the old one and in went the new. In about 10 minutes, not including gasket making time.
And the noise was still there. Bugger. It's the alternator.
Now I have always regarded electronics with a great deal of suspicion, and alternators are at the top of the list. After all your auto electricial always "sends them off" to be overhauled, usually by someone called Keith, or Werner. The conversation usually goes something like this:
Auto electrician puts both hands on hips and shakes his head knowingly "Hmmm no, I can't sort that out. We'll need to send it off to Werner. He'll know what to do. Mind you it'll cost you." Toothy smile..
In my mind I see a tiny rickety galvo shed in a backstreet. There is a sign over the door, but it's filthy and illegible. The shed is packed floor to ceiling with teetering wooden shelves overflowing with a million dusty, rusty car parts. Morning glory vine grows over the roof and in the one window. In amongst the confusion is a small elderly man with wild hair and thick glasses, wearing a grey shop coat. Wordlessly he snatches my alternator, shakes his head and grunts, then, cackling, waves me to the door....
So it was with trepidation that I decided to pull it apart and replace the bearings.

As it turned out it was simplicity itself, and the alternator still seems to be working after my efforts. Oh and yes, the noise has gone.