I fear that the free market argument here is "You guys set the rules by which we were able to grab all your money, so us doing that is your fault".It certainly quite the thing to defer to the free market and then not actually contribute to it. Governments ought to be just as willing to refuse business to companies that screw them as individuals are. In a way, not going after sucky companies is itself anti-business.
Although a key problem here being that the water companies are not free market: they are regional monopolies. They cannot be allowed to fail because people need clean water supplied and sewage removed. Hence the regulator ("Ofwat"), to provide oversight compensating for the lack of market competition.
From my understanding, Ofwat was relatively on the ball in the early days of privatisation, but latterly not. Although quasi-independent of government, I think it extremely likely that Ofwat's complacency reflects government complacency. And I really mean the Tories here, who are far too smugly hand-in-glove with elements of business and inclined to let them run riot, and who haven't been paying attention to a lot of things due to Brexit and their own, catastrophic, internal psychodramas, chaos and infighting.