I just watched a movie from 1953 that has an English party and a guitar player who's playing reminds me of Bill. The movie has an ending that is unexpected and surprisingly wacky at best... the dues ex machina of 1953. There is an aesthetic to the movie that fans on this site will recognize. And I don't mean that it is quirky -- though the ending certainly is. Loyd Bridges is the star of the movie with Leslie Phillips and Alan Wheatley as the Scotland Yard inspector, who I remember as the Sheriff of Nottingham in the 1950s Robin Hood TV series. You will find the movie on Youtube: https://www.youtube.com/watch?v=ajdBQii5zSk
One last thing. People either hate or love the ending. What comes to my mind is a line from another Loyd Bridges movie: "I picked the wrong week to stop sniffing glue." It's that shocking! I hope people enjoy it!