Two series of six episodes each were made in 1992 and 1993.

A third series of six episodes started on 16 May 2011.

In 2013 this was followed by a 4 episode series.

Only one series, of six episodes, was made in 1978.

Two series of ten episodes each were made between 1991 and 1992.

This film is the first in a series of 8 episodes made between 1980 and 1994.

This was to be the final series of 26 episodes.

A second series of four episodes began on 12 July 2011.

A third series of 15 episodes started in September 2011.

Two series of six episodes each were produced in 1964 and 1965.