Fantastic help gregoryoftours. I had convinced myself that at very least the inner 45 degree bevel of the bearing should abut to the bevel on the crown race to offer some kind of mechanical stability... and that I was now in some-kind of dilemma where I would have to find either a bearing with different angled bevels on the inner and the outer rings or that I would have to remove crown race and find another.
You're so right it is disconcerting how unstable it feels and it's as if the bearing is just balancing on the crown race with absolute minimum engagement.
These comments in this forum have given me the confidence to crack on with this.
I fitted a stem just to hold things together until I get a chance to come back to it and it doesn't feel loose in hand, it feels solid with just the stem. I'll firm this up once tube is cut tomorrow.
Thanks again for your help and everybody else. I had visions of hauling this off to the bike shop and I didn't want to do that.