Because Bryan Hitch is using Sir David Niven as a model for Alfred Pennyworth You know David Niven?
That's the fellow English actor, memoirist and novelist, notable acting roles included Squadron Leader Peter Carter in A Matter of Life and Death, Phileas Fogg in Around the World in 80 Days, Sir James Bond in Casino Royale[...]
David Niven Archives
https://www.youtube.com/watch?v=S0veuSLLWZ0Video can't be loaded because JavaScript is disabled: A Matter of Life and Death – official trailer – 4K restoration (https://www.youtube.com/watch?v=S0veuSLLWZ0)
A Matter of Life and Death starred David Niven as a bomber pilot trapped on his damaged plane as it goes down on the English coast[...]
The film was cast with a "who's who" of Hollywood heavyweights, including Bette Davis, Mia Farrow, Maggie Smith, Lois Chiles, Simon MacCorkindale, Jon Finch, Olivia Hussey, Angela Lansbury, Jane Birkin, George Kennedy, Jack Warden, and David Niven.
The Hollywood Reporter
Warner Bros.
Kenneth Branagh's master detective Hercule Poirot might be getting a pretty "wonder"-ful co-star in the form[...]