When Ernie is hanging from the helicopter it is evident that two separate sequences were shot. In the shots with Ernie he has his right hand holding on to the winch strap about 18 inches below the point where it joins to the winch wire. In the shots with the stunt-man, his right hand is holding on immediately below the join to the wire.
As Eric mimes Ernie's song he leans over the balcony and sees the sheer drop down to the sea; soon after Eric does fall over the balcony but crash-lands onto a group of people having dinner.
When Eric and Claudette drive off in the Ford Mustang after having offloaded Ernie the last back projection shot before the scene fades is one of just Eric - but Ernie is no longer to be seen running after the car in the background.
As Eric tries to pour himself a cup of coffee he spills the milk on the outside of the jug. In the next shot the jug is clean again.
In the sequence where Ern is winched down from the helicopter to save the waterskiing Eric, the bottom of the back-projection screen is occasionally in shot behind Morecambe.
In the sinister villa Eric Morecambe can be seen testing the floor with his toes (in his open toed sandals) where the floor opens.
The camera casts a shadow over the girl in the black-and-white bikini as it pans across to follow her passing Eric and Ern's changing huts at the beach.
Shadow of camera is visible on the wall to the left of the kitchen door at the Villa Tulipe when Ernie first enters it.
Shadow of camera crew is visible when Eric and Ernie cross the reception area at Le Touquet airport to meet Marcel.
In Claudette's room, when Morecambe and Wise are following her, at one point, she seems to be glancing at the bottom of the door, presumably waiting for the note (her cue) from Morecambe and Wise. As she collects it, it seems obvious she was expecting it.