When Leslie talks to John outside just after his (Leslie's) morning presentation (39.48), the time on John's watch jumps about10- 15 mins every shot.
Detective Albans offers to play "Rock-paper-scissors" with Alice Tavner, the protagonist's wife. However she call it "Rochambeau" which is the French language translation for the game. At no point prior to this does the narrative ever make it clear that Alice speaks French or would understand it if it was spoken to her.
Detective Albans offers to play Rochambeau with John Tavner (aka Lakeman) asking in French. She has no reason to believe that he speaks French as they have never met before. While this could have been explained if she believed that Tavner/Lakeman was the man that her daughter met in their home, the narrative gives no indication that she believes that this was more than the little girl's imagination.