Added the sow and a corresponding piget to the gallery, she's pretty distinctive. Aside from the social media material linked here and in the news thread, Whipsnade usually have good signage on their enclosures. I'd argue, aside from the label and the sow, that the piglets have squat faces and the hair sets them apart from those of a mass pork pig.
As @Lafone has pointed out, Middle Whites tend to have short almost squashed looking snouts which helps differentiate them from similar looking white breeds.
