Series 1, Epidode 4 - "The Big Fix" IMDb Page
Series 1, Epidode 24 - "The Reluctant Witness" IMDb Page
Also starring John Gregson. The series follows Commander George Gideon of Scotland Yard and his family life.
Stan appears as a character called Detective Inspector Wallace, a bit-part regular at the Station, and he has quite a few lines of dialog in the two episodes he appears in. The credits on IMBd and the DVD box set are extensive, so it's strange that Stan's speaking part was never listed. There were a total of 26 episodes, so many thanks to Bernie Peal for his eagle-eyed watching of all the episodes to locate Stan's appearances.