I have read the other topics on this forum and having difficulty removing the fuel cap due to excessive vacuum I suspect the breathe valve is stuck, However the only pipes I can find are behind the access panel in the wheel arch, I have a disc version of the workshop manual which indicates that one is the breather but is simply connected to the fuel filler inlet, I can't see this doing much breathing as the fuel cap is air tight. is this the pipe I am seeking with the ball valve?