Now its the regulator!
The dial face is bent so the needle doesn't travel. I wondered why I couldn't adjust the pressure before - I thought it was just me, shame it could have been replaced when the tig went back.
So fuck it, I couldn't face sending it back, took the clear plastic front off, bent the face down and also in by taking the back off which seemed hinged but was tacked on so that had to be araldited back on.
It worked. Not that it made much difference to my first attempt !