Visible crew/equipment: When Rodney and Del are back in their own flat, Del is pouring a drink, the shadow of a boom mic can be seen on Rodney's shoulder right up until Rodney walks away.
Visible crew/equipment: When Del goes back to the bar after realising that Debbie is his, in the top left of the screen, a shadow of a boom mic can be seen moving away near the "Carlsberg" sign.
Visible crew/equipment: When Del and Rodney are in Debbie's flat, Del and Rodney are talking about June not having a record player. A shadow of either a camera or a crew member are visible on the open front door.
Chosen answer: An apparent long string of illnesses.