Pyrotechnic

Hello All,

I have a 2009 (B8) A4 saloon with the 3.0TDI engine.

Around March time it developed an oil leak. After ignoring it for a couple of months and just topping it up every so often, I finally took it to a specialist. They diagnosed that it was coming from the exhaust manifolds (both sides) and without removing the engine and then manifolds, that's as far as they could go.

I got the car back and took it to a local garage instead for them to work on it (half the hourly wage...)
He (and everyone else I've mentioned it to) didn't believe it could leak from there and said he'd have a look before going ahead with removing the engine and said he suspected the valve covers.

Spoken to him today, and he's confirmed it is indeed leaking from both exhaust manifolds... (above is dry)

Some facts:

1) It started leaking just after a service and Terraclean.
2) It drives absolutely fine, no loss of power or economy (getting 40+ mpg, even got 46 the other day).
3) It doesn't smoke, at all (which no-one can understand either. Surely if there's oil in the exhaust, there should be large, black clouds coming out the back...).
4) DPF is dry.
5) Turbo intake has a slight misting (he seemed to imply this was normal I think?)
6) Mentioned EGR pipes were also wet.

He's suggested either turbo or even an internal crack in the engine. He's still got the car is going to speak to a friend who is a MT at Audi to see if he's got any ideas.

Everyone I speak to says these engines are bullet-proof. Trust me to get the duff one.

Any ideas?