If my memory serves me well, there was no way of selecting reverse whilst airborne on the VC-10, and after having one go into reverse on its own at 35,000ft I can see why. In flight reverse would have only been used to increase rate of descent and the VC-10 had 6 great big spoiler panels which could all be deployed at once as speed brakes, and they usually satisfied any increase in rate of descent required.
Now the Trident and Concorde could use to a limited extent engine reverse in flight
Regards Brit312