Hi Barry
Re the best way to pack for mail.
Personally I would not send any fresh food items by mail, I would use a chilled / frozen courier service.
That said if you are to use the mail I suggest that you pack the product in dry ice or ice packs & maybe freeze before sending, also use a next day parcel service with a before 10 delivery so that the product is not out of chill conditions too long.
Remember you are responsible for the goods up until the best before date.
Below is a link to the manufacturer of polystyrene cases
http://www.styropack.co.uk/display/index.php?m=1Hope this helps
Regards
Sausagemaker