The Sweeney: Selected Target (S3E1)
http://www.imdb.com/title/tt0714457/combined
You won't get to see these bits on the sanitised ITV4 repeats but in the uncut version some stills of a B&W photo session are shown on-screen in the lead up to a break. And later on someone is seen looking at one of the photos.
In the ITV4 version they are only seen getting ready for the photo session.
Judy Matheson has a small speaking role and is credited, Suzy Mandel is not credited.
Judy Matheson
http://www.imdb.com/name/nm0558556/reference
Suzy Mandel
http://www.imdb.com/name/nm0541681/reference