If you haven't had a chance, I reccommend reading some of the books. They are very informative.
Yep I knew what cob meant

They talk about it in the books.
My husband was going to go see them when he had gone on a trip for work last spring/summer. When he told them where he was coming from, they told him that it wasn't necessary and told him where he could find some cob buildings local to the area he was in. He ended up going to one of them and spending the afternoon plastering a garden shed in a park. He had a great time and really enjoyed it.