Audio problem: Near the end, Suzanne puts the dishwasher on, which is in the kitchen, near the long kitchen table they are all sitting around. At first, we can hear the dishwasher, not very loudly but it's there, but when they expose Suzanne as the killer, the dishwasher is all but silent even though its been running for at most 10 minutes, so it should still be noisy.
Audio problem: When everyone is leaving the restaurant and walking down the street, some are going off for a night cap, Rosemary says she can't go because she has to work tomorrow. But her words and her mouth are out of sync, as are the others to a lesser degree.
Answer: Regents park.