Charles Dance mentioned in his Production Diary that whilst they were casting, he got a phone call from Freddie Jones (who played Jan Pendered), who, having received the script, said "P**s-poor part, but I'll do it because I'm in love with Judi Dench."
Krzysztof Siwczyk was considered for the role of Andrea when director Charles Dance saw him in a re-run of Wojaczek (1999). Sadly, he then attended a Q&A session and deemed him to have grown up too much since the film.
The trivia item below may give away important plot points.
In the film, which is set in pre-World War II 1936, the sisters go to London to see Andrea play in concert and meet him afterward. In the novel, which is set in pre-World War I mid 1910s, after Andrea departs Cornwall for London the sisters never hear from him again.