Quote Originally Posted by angrybear View Post
There's little can be done but I'd ask to be shown the valve & the test it has failed and mention that you were not aware the DIN outlet was tested under BS EN 1802 only the cyl-valve fit, better still if you know the thread & can refer to the cyl-valve thread by size, I'd even ask to see where it says the outlet needs testing in the procedure, & make it clear you think they have caused any damage to make it fail.

If they think you know your stuff they're not going to try it on

Luckily I trust the chap I take my gear to & he knows I used to work on HP gas systems & cylinders.
This sounds like a sensible approach... At least if nothing else it may make them think twice about trying it on (if that is what they are doing!) if not then theory would have it they should be sympathetic and at least properly explain and demonstrate what is happening.