This episode has a James Bond connection, as Michael Kitchen appeared in 'Goldeneye and The World is Not Enough, Rosamund Pike appeared in 'Die Another Day and Edward Fox was in the unofficial Bond film 'Never Say Never Again' This series is written and created by Anthony Horowitz who has also written two James Bond novels.
The German bomber that appears in this episode resembles a twin engine Dornier Do-17, which would be correct in 1940.