I now have two new crowns fitted -- a gold one holding together the cracked tooth where the gum has been healing for the past 18 months; and a porcelain one that could be fitted onto the remaining bits of the decapitated tooth, even if it is set a bit low.
The former took a lot of wedging to get into place for the test fit, the neighbouring teeth having closed in on the gaps that had been widened to allow a crown, and a lot of work to prise free again so all the glue could be applied. I can feel it still as being tight against the other teeth, but hopefully that feeling of teeth in bandage should fade in a few days as the teeth jostle about.
The other went in easy, and we hope that the lashings of glue will hold -- otherwise it's a root canal on a live tooth, and fitting a post that will be needed. *ugh*