Scott Gall could well have sold his shares due to the approaching 'closed period' and secondly the options that have been sold may well have had an expiry date by which date they have to be sold.
Personally I always approach option sales differently from straight share sales as they can have many influences.
Additionally it is never wrong to take a profit both in Scott Galls case and Chefs as you can always buy the share again.
I continue to hold ahead of the Trading Update with a target price of 125p