Sorted it. Blocked gas pip. A bit of the rubber from the seal in the cylinder had come off and had travelled up the pipe.
Picture of weld attached
Now all I have to do is learn to weld
Loosened everything off and I could quite easily pull the wire through with pliers. I don't think that is the problem but if it doesn't end up in a skip I'll buy a metal lined one.
I've done a few mods. I've stabilised the rollerd by bridging them with a metal support. I've also done the mod to isolate the feed motor supply so I'd doesn't suffer from current drops. The liner is plastic but new. The problem is I'm getting no penetrative. Welds are just globs on the surface...
I have a sip handymig migmate which for love nor money I can't get it to produce anything close to a decent weld. I have never really welded and have no idea whether it is user error or faulty / rubbish kit. Thought is if someone is willing to have a go with it and can manage a weld then its me...