I would suggest you try the British board. Boris Atha is usually pretty good about the Euro tables. On this board, I'd defer to Alan Cribbs. Though I don't ever recall him mentioning Leonhart.
I assume you can still get parts, but you may have to order from overseas.
The value probably isn't much in America unless you can find a collector who specifically wants that table. I doubt it would be worth the effort to itemize for insurance purposes. You could always put it on ebay with a reserve. You might get lucky.