Usually Stewart never smokes. Once he explicitly states, "I don't smoke." (In "Who Plays The Dummy".) Yet in this episode - and this episode ONLY - he is once seen holding a cigarette, and once actually smoking it.
Kirov manages to batter down a heavy wooden door but when confronted by a lighter door with a glass panel he gives up and walks away.
The ordnance sergeant is clearly dubbed.
The body is supposed to have been found in Kent but Jason says the the plane flew over Hastings which is in Sussex. Additionally the chalk cliffs shown are the Seven Sisters, a Sussex landmark and some 25 miles from Hastings.