Fawlty Towers "Communication Problems" episode. Who does Basil think Winnie is?

In the Fawlty Towers episode “Communication Problems,” (the brilliant Torquay-hotel-window episode) there’s an exchange in this scene (starting at 0:39)

Major: I went to the theater of course with Winnie Atwood (sp).
Basil: Winnie Atholl (sp)?
Major: Marjorie Atwood. I used to call her Winnie because she looks like Winnie.
Basil: She’s not black!
Major: Black? Churchill wasn’t black.

The only black Winnie I know of is Winnie Mandela, but I don’t know if she was that famous in 1979. I had no luck finding anyone famous named Winnie Atwood or Atholl.

Winifred Atwell, I’m assuming.

Thanks. That’s been bugging me for years.

I’d never heard of her before, but then I’m not a big music aficionado. It looks like racism kept hers from becoming a household name in the U.S. That’s a shame.