JK's sure does make some damn good cider! Definitely my favorite. In fact, I still can't decide which of their 3 varieties I like the best.
As far as recipes, it appears that it's difficult to replicate. There has been some threads here discussing trying to mimic that cider. You can search here for JK Scrumpy and pull up those old threads and there was at least one where Bruce Wright of JK's piped in so check that one out. The key is in their organic apple varieties, long fermentation and the wild yeast present at the cidery.