Has anyone got a US Westy with the auto stop valve on the gas tank? Ours has finally run out, but the red 'reset' button seems to be stuck.

I'm not sure if the button should be free enough to operate by hand or by water pump pliers. There seems to be a lot of discussion on the samba about propane stores being unable to fill tanks due to stuck auto stop valves, has anyone had issues with a US gas tank?
Cheers
David