View towards the window site of Steed's living room. The tiger skin rug on the sofa appears for the first time in Steed's flat in the episode The Golden Fleece; it's not there in the first episode in his flat, The Nutshell. On the picture on the right side, one can see a leather chair that matches the sofa, but the color is lighter than the couch. There's a small coffee table, that usually stands here or closer to the mantlepiece. The sofa which stands in some episodes in front of the fireplace is missing. Behind the back of Mrs. Gale is a bookshelf, which later got replaced by the door leading towards Steed's bedroom.
Death of a Batman: Look towards the bedroom door and the spacious windows. In the picture, the woolie has been replaced against a way too large ship painting, which usually hangs outside the flat at the wall opposite Steed's front door.
Cathy Gale in front of the fireplace in Death of a Batman.
Mirror left to the mantlepiece - the widest angle ever seen to the left of the flat in episode The Nutshell.
The Wringer The Wringer Second Sight The Golden Fleece
All done with mirrors - backwards shots of Steed's living room. The mirrors are there since episode The Golden Fleece, but are different in number, height and position at the wall to the kitchen section in various episodes. They are missing in early episodes of series three such as in The Nutshell .
Steed's desk

Concealed behind a row of false books above the desk is a secret radio reciever, that Steed used only once in The Nutshell. It's gone in later episodes, as this wall is decoraded with mirrors. During other episodes, such as Lobster Quadrille, he is simply using a table as the desk. It also serves Steed as a table, because he's having breakfast at the desk in The Medicine Men..
The oil painting of Steed's grandfather (?) above the mantlepiece hangs in this place until the last episode of series 3.
Then it got replaced in Lobster Quadrille by another painting showing Mrs. Gale (I guess it was a gift from the studio or the production company to Honor Blackman, who was leaving The Avengers for the Bond Film Goldfinger).
Fanart
Outside Home Living Room 2
Instead of the mirrors - a hidden compartment in The Nutshell
John Steed's Flat - No.2
Living Room