OK, I checked mine over the weekend.
It was an "F" version, and both check valves worked perfectly, holding up very good pressure, and closing positively. I wasn't able to check the main valve though, although I did clean it with some carb cleaner, and none leaked from where it shouldn't. (BWA engine in a 2007model year, for reference).
Don't do what I subsequently did though, and sucked on the valves after dousing them with the carb cleaner - a lung full of xylene fumes is not nice!

:embarassed: