KFC Ad Banned - Burger Made To Look Bigger

A KFC TV commercial has been banned due to "misleading the viewers over the actual size of the burger". The ad is for a KFC mini-burger:

The woman in the advert may have had small hands, the KFC spokesman added. And they said that the burgers on TV had been cooked in a KFC that day and were really from the shop.

The defence of the fast food company is typical - "...the snack was called a 'mini' burger and it was only 99 pence so it was clearly smaller."

'Clearly' smaller? How is the consumer supposed to make that assumption?