TV non characters

In the 1990s sitcom "Keeping Up Appearances", Hyacinth would often speak to "Sheridan" on the phone, and yet they were never seen onscreen. I assume that was one of her daughters.

Also, in "One Foot In The Grave", Victor Meldrew's neighbour would often reference his elderly mother, and yet I don't remember ever seeing her at all. Just vague, brief references, or unclear glimpses of her behind net curtains. (When I say "neighbour", I refer to his other neighbour, not the one played by Angus Deayton).
 
Sheridan Bucket is a fictional character in Keeping Up Appearances. He is the only child of Hyacinth and Richard Bucket. Sheridan is a mostly unseen character in the series, despite his head perhaps being seen in the beginning of "Let There Be Light" and perhaps a picture of him as a young child in the intro.
 
Sheridan was her son who enjoyed the finer things in life like silk pajamas, he also had some very close male friends!

Paul.
 
Though Peter Falk's actual wife did appear in a number of episodes, I believe.