Trying to identify a television play

Way back in the early 1980s (?) I watched a TV play that was set in a mental health hospital, where the ward was full of crew members from world war 2 bombing raids. During the day, the patients simply laid in their beds; seemly comatose. However, at night, once all the staff had gone, each of the patients got up and placed a chair in the position of where they would be inside a bomber; and they would re-enact their last flight.

Initially, all the sounds were made by the actors (engines, etc) but as the play progressed the sounds were replaced by authentic sounds.

I remember really enjoying the play but never seeing it again and I cannot remember its title or very much else about ti.

Anyone any ideas?