I bought from them. What they did was they have "contract fitters" who work for them, but are also "independent"?
So i picked out which carpet I wanted, they sent out a fitter, who measured and told me how much I needed, number of grippers, metal bar thingys etc, and then i paid carpet right for it. He picks the stuff up on the day of fitting, comes over and does it. I then pay HIM for the fitting (which I am told the price of before).
All good. Prices were comparable with other places.
If you want, you could get your own fitter, who writes down what you need to buy from carpetright. He can then pick up the stuff and do the fitting. using their own fitter just saved me bother of finding one.