As far as im aware if you bring any bottle not certified for UK use over here any proper fill assistant will not let you fill your tank,
Imo its stupid scince DOT testing is much more specific than PYE as far as im aware =\
but hey the law is the law.
As for sending it off, no I dont think this will as when they test theyre tanks for safety theyre pushed to the limits of actualy explodeing to record how the bottle explodes ect.
So you can send it off, youll just have to glue it back together when they send it back