Hi , my outside tap is leaking from the connection inside the house. It’s very hard to get at even when I’ve removed the fridge and reached behind the units. I can see it’s leaking from the white plastic screw on hose . Does any body know the diameter of the washer I would need . The tap is from wickes I think , it’s one of those which makes a hole in the pipe as you tighten it on. Hope this helps .. thanks