you need to watch Cadbury as a corporation very carefully
They have been reducing the standard weight of many of their chocolate bars. They chocolate bars look identical - even the price tag
I recall the time when they reduced the weight of their standard Chocolate bar from 250g to 200g (20% REDUCTION) and changed the packaging to a thicker cardboard type packaging which made the bar appear similar in size. Very sneaky whilst not reducing the price by 20%.
250g............................... .............................. 200g
http://i.ytimg.com/vi/30wsqtiBrVw/hqdefault.jpg