in the last Mrs. Peel episode
didn't it turn out that her husband looked just like Steed?
I seem to recall that he was dressed similarly and looked similarly like him but it was played by a different actor.
According to trivia I looked up it said the following. For many years it has been claimed that Patrick Macnee plays Peter Peel when he drives Emma off at the end. While this appears to be so in the close-up shots, Paul Weston, Stunt Coordinator and Second Unit Director, played Peter in the long shot as they drove away.
In the kingdom of the blind, you're the village idiot.
I just saw it again and as she's driving away she looks at her husband and then back at Steed and smiles, like she knows the resemblance. And Steed has a surprised look on his face.