Is a york flange simply a surrey flange with an adapter to convert the thread that screws to the tank to female because when I search for a york thats all I find. My copper tank has a male thread that is definitely part of the tank so I know I need a york flange but I thought by using this type would raise the shower inlet pipe by at least 30mm and defeat the object slightly. I gather the male thread at the top of my copper tank should be the standard 1" bsp does the 1" relate to the bore as the outer measurement is 1.25".