At the beginning, Truly and Clegg are looking on the floor for Clegg's collar stud. It appears to be Truly crawling behind the sofa, but all that is seen are his back end, legs and feet. As the camera pans along the front of the sofa, it stops at the other end, and Truly appears, facing the camera, too quickly for him to have crawled and turned. Apparently, a "stunt" man was used so that the 89-year old Frank Thornton didn't have to do the crawling.
When Toby asks Barry if he has seen Morton, what is heard for Barry's reply is not what his lips say.