It still makes the noise.
https://drive.google.com/drive/folde...usp=drive_link

Against the advice of nearly everyone, (on here and in person) I changed the bottom bracket from a steel stronglight to a titanium stronglight. I also replaced the pedals.
So it's not either of those two things. The chain is only 1.5 years old, and the freewheel is only 1 year old. A cheap sunrace one. When I remove the wheel I can feel some play on the freewheel side to side, when the bike is upside down (I have no stand) and I pedal and then let the wheel spin freely you can see some "wobble" to the freewheel.

But again, it made the sound before the sunrace freewheel was changed. I'm tempted to try changing the chain. Or try another freewheel.
I'm also slightly suspicious of the rear derailleur, it's never shifted very smoothly. If money weren't an object I'd get a dura ace 7400 rear derailleur and matching shifters and freewheel and switch to index. Will maybe do that anyway.

I'd really like to figure out what the sound is though. Could it be possible that my Tipo hub has some sort of issue, like the bearings? Could it be the skewer, which is not the original campy one but a cheapo anti theft one? Would welcome any thoughts.