In the plastic spacemen cereal fun advert, when the boy says "Mum, mum, I've found a corn flake" the voice is Tim Brook-Taylor's, not the boy.
The jingle at end of the comedy advert for Plastic Spacemen cereal, the singer refers to plastic space guns not plastic spacemen.
Despite his character being deadly serious at the time, Graeme is clearly struggling not to laugh when he delivers his line about towing England outside the five mile limit.