Ok, two things going on.
1. The archtop bridge is destined to fail. It's just a bridge to far for my skill, as to get it to work the neck need to be re-angled steeper, I've put that one in the too hard basket
The option for me is to some how come up with a thinner bridge base, so I have ordered one.
But if the bridge post do not line up then I am still screwed.
At the moment I have a temp base made by Staedler, I think the model is a 2B.
2. The neck issue seems to have been that it was getting skewed because of that little undercut in the neck slot.
It lines up now just a little bit north of the side join. the alignment over the pickups is also much better.
My options if I can't sort the archtop bridge is to re-drill the bridge post hole. It's not my favored pathway, but at least it is a proven outcome.
Cheers PK