hi all. im in the middle of trying to order some fittings and pipes to do my radiators. ive been looking on toolstation website and i want to know if i need to order the PEX inserts (Item no 42610 and 21648) when using reducing T (item no 39606) to connect a 15mm copper pipe each side of the T and a PEX barrier pipe 10mm in the reduced bit. or do the fittings already come prepared to connect to plastic and copper? thanx