Thanks JoeTBM for the response.
You have a good point re. bearings not seated properly, but they feel very good. Smooth running and no play.
I tried the aluminium disc on top of the nut (pic in album, thanks). I have a vague recollection of that setup, but the bearing really does not seat properly. I think that alu disc is the main water seal for the top, but it's not going back together as easily as I hoped. (The benefits of photo documentation!)
The cross sectional diagram that was kindly posted earlier doesn't show these aesthetic outer bits in much detail.
What should one do? LBS? 😂👍