What is a 'grape punnet'?!
Answers:
A punnet is a small container, usually housing some sort of berries inside, although often associated with other fruits. So, presumably a "grape punnet" is a punnet full of grapes! :)
An example of a common punnet one might expect to see in a supermarket;
- http://www.szp.co.il/pics/Ribbed%20punne…
A punnet is a small basket (usually containing strawberries). I've never heard the term 'grape punnet' specifically, but it's presumably "a small basket of grapes".