The fictitious prison named Parkmoor was previously used in Thunderbirds episode Vault Of Death [23/12/65]; and appears again in Crown Court episode Intent To Kill [9-11/5/73]. "Parkmoor" is clearly a composite of the names of two real prisons (Parkhurst on the Isle of Wight and Dartmoor in Devon).
This episode seems to indicate an increase in the production budget. The set is more complete, camera angles are more adventurous, showing the side of the court opposite the jury previously not seen, presumably because it did not exist.
This episode is the first not to begin with photographs reproducing the alleged crime, although the photos do return in the next story.