I use KensalGreenCarpetCleaners for my carpet cleaning. Since getting the carpets steam cleaned a few years ago, I have been having it done fairly consistently since, every three months or so, as it really does make the place look a lot nicer. The company are very good at the steaming, and even offer dry cleaning services, which I have used for tougher things, like red wine spills. I am always surprised by how cheap they are, and have recommended them to various friends and family already!