So I have two rattles, one of which may be the same as yours. Its on a 2013 D40.
At 110kmh I get a high pitch rattle, and this is actually the lock cylinder to the glove box. As you are driving and the rattle starts, push the cylinder in. On my D40 I havent been able to stop it permanently but WD40 helps for a few weeks.
Second rattle, this one is deep, and comes from the AC duct / back of dash and only happens if I rev up the car from 1500-2500 as it is in the grunt of the rev range. I havent figured what this is, but a friend who also has a D40 says, its just loose dash fixings way back in there, that vibrate as the ute revs up.