George and Lynne are out and about. Lynne is looking in the window of a flower shop and George is outside a fruit and veg shop. Lynne tells George that as it's her birthday he ought to buy her a bunch. George asks whether it should be grapes or bananas.
It's Lynne's birthday so they must be out for the day, perhaps for a leisurely lunch in a quiet town outside of London. As they stroll from the restaurant to the car, they stop to take in the quaintness of the small town. Lynne likes flowers but George is fascinated by the fruit and vegetables. This is because the lunch was quite expensive and he could only afford one course at the restaurant. George liked his lunch, but feels as though he is not completely satisfied so wants to finish off his lunch with an orange.
Lynne smiles at the end after George's joke as she thinks that he isn't being serious. She has already had her proper present, which was probably some jewellery or perfume or negligee. George is half joking. He is not really going to buy her some fruit, but it is his way of saying “I have bought you a necklace (or perfume or negligee) and taken you out for a very expensive lunch, and you still expect me to buy you flowers. No, it's fruit or nothing for you.” Lynne liked the joke so much that she decided on grapes. George's plan has backfired but at least he only had to pay a pound for a bunch of grapes, and that's a darn sight cheaper than the black forest gateau he had his eye on.