Shetland Paul
You can use the term "Free range GOS" only if your GOS parents are pedigree and registered and their offspring is birth notified (hence the benefit of the meat cert as advocated by Hilary'smum), otherwise if they're not you could only call them "Free Range Pork".
The GOS club has fought hard to protect the GOS name as some of the alledged quality end supermarkets have been purporting to sell GOS bacon & ham when it only cross bred, their packaging says sired by GOS boars but the mothers are commercial white pigs so its nothing like the real GOS product and in this way they're duping their customers. You can find more info on the LACORS ruling relating to this on the GOS website.
HTH
Mandy