Police Raids Uncover Cannabis Factories in Rented Houses in Exeter

A little bit of local news I spotted at the weekend. This is clearly going on all over the country. There have been entries on the blog from Belfast and Scotland. Presumably other local papers are reporting their own local stories. Vietnamese and Chinese gangs have been blamed elsewhere, but no-one was found at the scene in sunny Exeter. So what is the nature of the organisation here exactly? Is it individuals or is there a loose organisation, with central capitalisation and marketing?