I have a boiler to be installed by a pro but I am going to fit radiators and pipe work myself. Can anyone recommend if I am best using compression or solder fittings? The pro told me to run 22mm from the boiler and I can spur off with 10mm to the rads. He also mentioned using plastic pipe that can be embedded in the plaster for running down the walls to the ground floor (boiler upstairs). Will that work or is it risky? Can I use plastic for the whole lot?