Factual error: It's Christmas Eve 1925. Tommy and his son leave a mince pie for 'Santa and Rudolph', but there was no reindeer called Rudolph until the 1930s. The character's author hadn't even graduated by 1925, and only began writing a book about a red-nosed reindeer in 1939.
Factual error: Lord Stamfordham has a paper before him headed 'London Constabulary Police'. There was no such thing.