Thanks Matt. That has been my ongoing No.1 suspicion for why mine is so particularly vibey, but thought the alignment idea might be worth a punt - even if a paint dot does sound highly unlikely as a long term alignment marker. Any idea what the dot is about then? I've not had my crank out yet so haven't seen one. It's not just a daub of paint on the end gear nut to show it's been done up to tolerance or anything is it?
Cheers
Wb