The plumber we've know for years played the devil's advocate when I spoke to him - no clips is fine, no insulation is fine, Speedfit in concrete is fine, no ducting over the plastic in concrete is fine, not recommending a two pipe system - well he'd look like he was trying to get extra work. One...
It has helped me. I hate confrontation and the builder has defaulted to saying "it's fine" to everything I'm unhappy about. Since I'm not certain I let them go but I now believe the plumbing has so many sub-standard aspects (at least six!) I have asked another plumber whom I trust to inspect...
It was and still is a one pipe system. I was advised to replace all the old rads. Most of the ground floor pipes have now been renewed. When I saw the corroded old copper pipes I asked for plastic where set in concrete, which the plumber misunderstood as pipes everywhere to be plastic. I did not...
I've told the builder who hired the plumber. He's insistent that it's all fine. I'm not living at the house yet and haven't seen the plumber in a while.