The Wrong Box
Here's a film aware it's a bit silly. Two elderly brothers in Victorian England are entered into a "tontine," an agreement where the last survivor gets all the money. Cue relatives plotting to bump them off and collect. It's not quite Ealing, but it does have Michael Caine.
Directed by Bryan Forbes · Written by Larry Gelbart, Burt Shevelove
Starring John Mills, Ralph Richardson, Michael Caine, Peter Cook, Dudley Moore, Nanette Newman