At one point in this episode, during the scene in which DCS Lockhart receives CG's wallet from Monty Drew, Eric Lander forgot his lines and a voice out of shot could clearly be heard offering him a prompt "Somebody killed him". This episode was either shown 'live' on television, or else if it was pre-recorded, the scene was not re-shot and the tape edited.
When Harry gets two drinks at the party, one is already waiting for him.
When Inspector Baxter is talking to Joanna Church in her dressing room, she tells him that she is going to a party later that "CG" will be going to, and suggests that Baxter meets her there so he can talk to "CG". However by the time we see him leave, she hasn't told him where the party is. Nevertheless, Baxter arrives at the party later that evening.