Not an oil leak, per se, but rather a light film of oil around the base of the turbo connecting pipe. This is (as I understand it) the small amount of oil that is contained in the recirculated exhaust stream as part of the CCV system. Pardon me if I have some of the details wrong. This link describes an issue with the diesel engine where the red flexi charge air hose line gets covered in oil from seal failure in the flexi hose. In that thread there are many people commenting that there shouldn't be any oil at all in the charge air hose line, but many other people say (and my experience supports) that a small amount of oil in the turbo air flow is a normal part of the re-circulation/anti-pollution system. If there is a seal failure and some of the turbo exhaust is leaking out, then a small amount of oil leaks out with it.

When I put a mechanics mirror underneath the pipe connection and angle it upwards I see a drop or two of oily liquid around the roughly 8 o'clock to 4 o'clock portion of the pipe connection. To repeat what I said in my original post, I see a mounting panel and bolt at the roughly nine o'clock position of the flange (yellow arrow), and an empty threaded flange (red arrow) at the (roughly) three o'clock position. So I'm left wondering if the bolt fell out and that is why I've got a leak. But I agree with you that realoem has been very accurate with quantities of parts - hence my uncertainty.