Hi Pere Sorry to hear of your troubles. I had a similar experience with British Gas, wanting to charge an extorsionate rate for a power flush. I wasn't even aware they existed, let alone what one was. I got a second opinion from a local plumber. He agreed it was beneficial. He didn't do them but suggested I try a plumber he knew. I did, he charged me less than half BG's fee, and indeed he was right. My system heats up far quicker, radiators are consistently hot, quieter, and when I remove them to decorate, I don't get dirty water everywhere. I would highly recomend the company who did mine.