hi Stewart,
You could possibly solder the inner part which has gotten detached to the inner crown. But you would need a butane torch to melt the solder. The process might end up destroying the crown though. The costs of it might not justify the result either and lastly the 'feel' good factor might be reduced. The easiest way (probably the best) is to source a new crown.
Good Luck!

: That looks really classic John. You don't see many of these either.
: Re, the crown. I've had a few crowns in the past that have suffered
: the same problem. I'd love to know if there us a solution. There
: is a glue called Liquid Metal, which is supposed to be as strong
: as a weld. I've often wondered if this could be a solution, any
: experts please chip in.

: Stewart