The protective suits worn by the boarding party were rented Michelin Man costumes combined with a different facemask.
The six computer screens along the far wall in the decoding room are actually microfiche readers.
Although broadcast seventh, this was the second episode recorded for Season 2. It originally featured Gan in a small role operating the teleport, which was removed when the decision was taken to move it to after Pressure Point (1979). Moving it to after Trial (1979) also lost a reference to Travis being en route to the planet with Servalan.
The crime Avon and Tynus took part in may be the fraud mentioned in Space Fall (1978), although this is not made clear. Further details of the fraud are given in Rumours of Death (1980).