So, after an initial excellent experience with BMW warranty with regards to replacing the alternator on my 320d, I have now experienced issues whilst trying to claim for another issue.
The alternator was causing I-drive issues and loss of electric assisted steering (which was quite frightening). Alternator was undervolting, but on my was back from London, the dashboard lit up like a Xmas tree and I had to stop.
Quick call the BMW emergency assist and the guy was with me within an hour. Did all his checks, said it would be ok to drive home at "sensible speeds" (only 30 miles left).
He followed with to Stratstone Derby, where it was booked in and repaired within 48hrs. (replacement alternator)
The BMW emergency technician said I should get the clutch looked at under warranty as there is quite bad vibration whilst on tickover and noticably worse when the clutch pedal is depressed. He said probably the bearing in the dual mass flywheel was buggered, allowing oil onto the clutch plates. He said, it is quite a common problem.
Stratstone said that it would cost £430 to drop the gearbox to inspect and that if it was clutch wear, it wouldn't be covered.
I haven't booked it back in as of yet.
Car has covered 56k with at least 40k of that being motorway mileage.