I'm sure yours will be fine, but I think my next test will still be clutching at straws. The air inlet pipe, from the air filter, to the turbo is oily when you rub it with your finger. Looks to me to be standard fume deposits, over time, from the cyclone breather and pretty dry. I've a feeling it would be wetter, as it is inside the IC pipes on the other side of the turbo.
The Mrs is collecting the oil and filter on the way home, so I'll get that in tomorrow and try the wing test with the cyclone breather pipe removed. That'll prove, one way or the other, if there's oil coming through there when the draw of the turbo is on it. (fingers crossed emoji)
@accynina