Although I have recordings of his serious works
Letters to Lindbergh, and the ones which include the Piano Concerto and Violin Concerto, none of which I am very familiar with, when I think of Richard Rodney Bennett I primarily think of the melodious opening to the 1965 Hammer Horror film
The Nanny with Bette Davis and Wendy Craig, which appeared at regular intervals in the late 1960s and the 1970s on UK Television. See:
It must have made an impact on me when I was young given I still remember the theme. It was from this that I first became aware of the name Richard Rodney Bennett.
After this I think of his score to Franklin J. Schaffner's impressive 1971 film
Nicholas and Alexandra for which I have the original soundtrack score, which I think is a bootleg. It was recently on a UK TV Freeview channel.
See:
I also have a rip of his children's opera
All the King's Men which was once available on LP. This is available in its entirety on YouTube:
See:
https://www.youtube.com/watch?v=mP-EGWBKzWU&list=PLKNYFzfTufPWwqrIcMdmge6cjTVUSHAiwThere are several recordings of his music in the British and Irish Music Catalogue on this site.