Hi Julie,
As a fellow devon dweller (North Devon in my case), I can recommend the NDS. There is not as much to do as at, say, Mid-Devon Show, but it is very family friendly. I am sure that there were a few pigs there last year, but that could have just been small children covered in mud, as the weather was about as good as it has been this year!
However, on the pig front, the majority of the pig producers that I know in this area breed for meat rather than showing, and you tend to end up with only one or two exhibitors at the shows throughout Devon (particularly with Berkshires, my breed of choice, where Ian and Maggie Todd win everything as they are the only ones who enter!!). However, the rest of the show is generally great fun, with the majority of people who are showing their animals being more than happy to talk to you about them.
Also, there is quite a variety of trade stands. Just hope that there is a bit of dry weather between now and next wednesday, or else take a good pair of wellies, as the site gets very muddy......
Cheers - have a nice time. I can't make it this year, but happily, can get to Honiton show on the Thursday..
Cat.