Steed and Mrs. Gale often have dinner or breakfast in Steed's flat. They use a small square collapsible table (that usually stands in the kitchen) and the chairs from the kitchen. When Cathy tries to find herself a new flat in the episode The Golden Eggs, Steed let her have his flat while he stays in a hotel. Obviously, Steed's apartment has only one bedroom and no guestroom.

Trivia: This breakfast scene above is a funny one due to a continuity error of the episode.
Steed and Mrs. Gale have breakfast twice during the episode, but Cathy reads the same newspaper on two different days.

Above the door; which leads to the bedroom, one can see some fishing trophies. The same props appeared later in other The Avengers episodes such as Dial a Deadly Number, or Get-A-Way!
The dark blue couch is a three seater with a corresponding armchair next to the staircase.

Sometimes one can see a houseplant behind the sofa, a papyrus plant, and a standard lamp, a (during the 60ths) modern spotlight.

Steed also has a small rubber bush, which stands next to the entrance door.

At Steed's left one can see his wine cabinet or his drinks cabinet, on top of it sometimes stands a modern metal sculpture.similar to that one in Mrs. Peel's first flat.
Living Room 1HomeLiving Room 3
A look inside Steed's wine cabinet in The Mauritus Penny.
Steed likes a good claret and in later episodes such as Death of a Great Dane or Dial a Deadly Number prove that he is obviously  a fine wine connoisseur.
John Steed's Flat - No.1
Living Room