[ChaZer]

Hey Giova.

I've read your private message. Though I will answer in this topic so everyone is able to read in case they face a similar problem.

I've already changed the clutch + dual mass Flywheel. The workshop replaced these parts with 'Luk' parts.

But, the problem stayed. The car will be in the workshop again in may. The Reason for this is the following.
As they replaced the parts, the company 'Luk' delievered a clutch without the guide bushing, which usually has to be renewed as well. As a result of this, the noise is still the same. They intend to build everything out again and replace the guide bushing with a new one.
I dont know if this translation fits. In German it is called 'Führungshülse'.
I've also had contact to "Dr.Krumm" via Facebook, a well known Mini mechanic. He stated as well, that this noise, you and me are "suffering" from, is mostly a result of a faulty 'Führungshülse' (guide bushing). I hope this answer helps you a bit. I will report, as soon my car is fitted with a new guide bushing.