The car went into the shop today to investigate the door noises I have had since new. I took one of the techs out for a road test and he heard the noise as soon as we left the dealership driveway and all through the short road test. He agreed it was quite annoying.
I left the car with them and collected it later in the day. All I can say is that it is very nice to drive without the constant crackling noises from the doors. It was a simple fix - they applied a treatment to the felt seals.
Prior to this I had cleaned all seals with water and had applied Gummi Pflege to the rubber seals. This had marginally reduced the noise.
If you are experiencing these noises from the doors in your F30 I suggest a trip into your dealership and get the felt treated.