I ordered a new radiator and valves from Victorian Plumbing (VP). The plumber came and fitted it. However, a few days later I noticed that one of the valves was leaking. I called the plumber out again. He turned the valve and literally the whole thing came off in his hand (with ensuing water gushing everywhere). I arranged for a new valve from VP and returned the faulty one (it was cross-threaded). All of that was fine and the plumber fitted the new valves and all of that is fine. However, the extra plumber's charge for this work was £192, which I have paid. I sent VP the invoice and they have just responded that the manufacturers are only willing to pay £100 of this charge. Is this fair/right that I should be out of pocket because of a manufacturer's faulty product?