 The sets were redecorated and reorganised several times to make it appear that Macey's transporter covers more ground.The transporter model, which re-appears in "Expo 2068", was designed by Meddings' assistant, Mike Trim.The incidental music for "Big Ben Strikes Again" was recorded on 16 April 1967 in a four-hour session held at series composer Barry Gray's private studio, where it was performed by an ensemble of 14 instrumentalists.