You should change your flame trap, as it gets older, you need to make sure it is clean or pressure will build up and cause leaks.
On your leak, I suspect the turbo drain line gasket needs replacement. They sometimes leak, and it is at the back of the engine. If you are able to safely look under your car, you can see a tube running from the turbo to the oil pan. It is the drain, and a leak at the rubber o ring at the pan will run up the pipe appearing as if your turbo is leaking. You'll have to clean it all off, and run it to determine the exact location on the leak.
The V70 is a light pressure turbo, and it seems young for an internal leak. Remember to idle a minute or two before shutting the car down if driving at highway speeds.