I don't think there would be any legal issue, peter, so long as the facts are correct. Any decent news article worth its cocoa has to have an 'angle' or/and a 'hook'. Make it too factual and balanced and it becomes reportage which really only works for weighty stories (for this read 'bad news'

).
On the issue of the price of chocolate, I recently heard a similar story from a producer here in Ireland and it seems that costs have gone up in that area, so rather than increase prices the producers are reducing portions. And if you think about it this may not be a bad thing in relation to health, smaller portions = healthier eating. Look at the size of packets of crisps these days, they used to be a small cheap snack, now they are a significantly larger more expensive snack. The result is that we consume more of what is one of the most unhealthy food imaginable. Similarly, bars of chocolate, once we could only afford 50g max for a treat, now we buy them in much larger sizes, and as a result eat much more. Chocolate itself is not that much of a problem, it's the amount of sugar involved that is the real issue.
So, paradoxically, the reduction of product sizes is a good thing even if we are getting less value. I sometimes buy a product that is not as good value as I could get simply on health grounds, because I know I will eat less as a result. Did I mention that I'm a chocoholic!
u.