Carluccios are an interesting beast. I met him once and was witness to his assistants crumbling face as his boss deviated from the script to adlib a somewhat racist joke. Ah well...
The coffee isn't theirs, it is a fairly large Italian roasters coffee, just rebranded. (Or at least it was when I last had it).
However they do put a strong emphasis on the coffee, employ people to just be baristas and do train reasonably - though I would suggest ordering a ristretto as their espressos are usually a little bit long.
I like that they serve the coffee with water on a nice tray and it is definitely one of the better high street shots.