Factual error: Prince Phillip is boarding the yacht, and seen in the background is a red modern vessel that would not have been around in that era. The vessel shows very modern signs of shipbuilding in its new shape, and modern rescue craft. With satellite domes located on the bridge.
Factual error: As HMS Britannia sails North, there is a disabled symbol on her stern. Pretty sure the RN wasn't interested in disabled accessibility in the 1950's.