Corrected entry: In the scene where Mrs. Parker has comes to the Goodfellow house to complain about the flower arranging committee, she says she has a bad heart. When Grace comes down the stairs she only catches the end of the conversation where Mrs. Parker is saying, "Your husband must be told," and then she runs to the kitchen and gets a frying pan to hit Mrs. Parker over the head. Afer Mrs. Parker drops dead, Grace says, "Well, she said she had a dicky heart." But this was said when she was upstairs and she would therefore not have heard Mrs. Parker saying it.
Corrected entry: In the opening scene, set in the 1960's, the train guard discovers a large trunk with blood leaking from it. He establishes who the owner is and when the train arrives at the next station the police are waiting. How did he manage to notify the police? Back in the 60's there were no radios on trains and the mobile/cellphone had not been invented.
Correction: In Switzerland, before the invention of mobile phones, train staff used to throw out toilet paper rolls with messages on them when driving through a station, so the station staff could phone ahead to the next stop if necessary. Maybe that's what was done here as well.
Correction: However, there is nothing to say that Mrs. Parker hasn't told Grace about her bad heart at some other time.