My Mini antenna broke.
I remove it every time I go to the car wash, and it's never been mistreated. The local Mini dealer told me it's not uncommon.
I found a better replacement. It's solid metal, and works as well as the Mini one. It also mates to the base better.
Here's a link. By the way, the 22nd pic is mine.
http://www.cravenspeed.com/products/The-Stubby-Antenna.html