Revealing mistake: On their first stop after leaving Walbrook Charlie and Susanna make love. Raymond comes into their room, Charlie gets mad at him, and when he gets out of bed you get a glimpse of the sheet that prevented skin contact between the two 'lovers'. (00:32:35)
Revealing mistake: While Ray is driving the car, in the next shot of them driving down the road, you see a police car driving very slowly keeping back the traffic behind them.
Answer: Susanna was there as well; Charlie just used the "date" as a reason for the three of them to go down for a drink together. He knew Iris wouldn't show up.