I’m wanting to connect a 20mm MDPE pipe to an outbuilding and need preferably a 15mm copper to 20mm MDPE stopcock (I know I can do it with a 15-20mm adapter and then 20-20mm stopcock). But I can’t seem to find one other than in brass with the screw down valve that I find unreliable in the long term. They seem to do 22mm-25mm and 22-20 but not 15 to anything plastic stopcocks other than one on Amazom that I’m not sure I would trust. I want a reasonable quality one as it will be in an access hole in the ground so not easy to change out if it fails Can anyone suggest where I might find one please?