In my half-baked British accent (because quite a bit of American east coast is also thrown into the mix), I say either Dah-na-vun or Dah-na-vin, depending on which accent is fighting for control (vun for the British half, vin for the American half--and it sometimes comes out more dahn-a than dah-na, which mostly depends on where in the sentence Donovan shows up, but on its own, it's always dah-na and usually vun).