Take any paperwork, certainly the account number - they'll probably give you a card with the number scribbled on in front of you - makes future swops easy, as well as going to an alternative agent if needed.
Still not welded yet, the 8mm hose i ordered with the welder is too big for the regulator / rectus 21 fitting, so gotta get some 6mm hose tomorrow.
But i've put my regulator on the cylinder, wound the knob right out so no gas flows, opened the tap, and it's only showing 200 bar, it's 9 degrees C in the shed, and cylinder has been in there over 6 hours now.
I note on the cylinder it's filled to 230 bar @ 15 degrees C, is 6 degrees below that enough to drop 30 bar?
Of course i suspect my regulator, its ~20 years old, and not been used for about 15 of them, been stored in a box in the bottom of my toolbox, but the gauge is a simple thing... pressure tries to expand the coiled tube in it and winds the needle round.
Considering upgrading to a 2 stage regulator, but blimey this is getting expensive