Hi Phillippa
I'm in the UK and haven't been able to get this working despite talking to the helpdesk. I ask it when is X's birthday, or when is my car service due etc, all of which are in my calendar, but it cannot give me an answer. Each time I just get ..... the next events in your calendar are....... etc etc..... similar to your experiences.
I'm not sure that the device can actually filter this information to date despite the helpdesk telling me that it "should" be able to.