It should come with it. But don't quote me on that
TBH I always thought DAB in a car was pretty poor but that was based on a couple of Minis I had for a while and I'll admit a certain amount of user error. Park in a place with good strong DAB reception (eg city centre) and tune/store your stations. I've done that and not lost a signal once. Previously I was having half arsed attempts at tuning whenever I remembered, hardly got any stations and then just gave up.
And thanks for resurrecting this thread. Interesting to read the OP's thoughts.