Just a note about copper and I wonder if others are finding the same thing in that a lot of copper pipe for sale just now is poor quality and in many ways like thin wall tube. I'm good with a bending spring which I sometimes use for speed over the bending machine, but a lot of the copper pipe just ripples no matter how careful I am. I suspect that perhaps a lot of pipe is being imported and not as good quality as our BS Kitemark stuff?
I use Speedfit and have not had any problems of any kind on a install. The problems I get to fix are builders, joiners, diy'ers trying to be plumbers and not following the manufacturers installation . Seen many joints with no inserts, even joints with flux in them. No wonder it gets a bad name. Incedantally, we've all been using plastic pushfit, glue and plastic compression fittings for years....on waste pipe. No stigma attached to that then?