Check out this thread: http://www.e90post.com/forums/showth...=414556&page=2
There is an image from BMW ETK which suggests that they used a different part from July 06 onwards, which could explain why the LCI cars don't appear to have the problem.
My car is pre-LCI but build date shows as 22/08/06, so i'm hoping it's fitted with the later part. When i swap to my winter wheels i will whip the inner arch off and have a look.
Here's the image from the other thread, with part numbers: