I think their flagship stores (Brent Cross & Deansgate) are possibly as much about having a presence as making money. That's only my opinion and not fact. Although at the margins they work to, profit is also highly possible.
As for the carts in shopping malls these are franchised and highly profitable. Also a big growth area for them. I know some franchisees started with one site and now own several, which would suggest them to be pretty lucrative for all concerned.