They don't sell yarn, just knitting needles and other related items. I've bought from them several times -- they often have the sizes that are otherwise hard to track down.
It doesn't sound as if you'll be visiting the Inner Hebrides (west coast), but if you are, a trip to Mull and Iona will provide not only beautiful scenery but wool made from local (and other) sheep: http://ardalanish.com
Lantern Moon used to make circulars that didn't curl. The cable and needle were attached but somehow could also move independently of one another. Sadly, they are no longer made by the suppliers in Vietnam. But if you ever get the chance to buy some, grab them!
I used to check in almost daily on the gansey group on Ravelry -- I found it very amusing. It was like politics, with disagreements and arguments about what a true gansey was, their history, and so forth. I haven't looked at it in months so perhaps it's kind of run its course.