Jimmy would probably not get the rights, because the translation was a work for hire. (see what happened to Jack Kirby’s descendants). So the money would probably have gone to descendants of the house of Stuart, unless the courts ruled that they should be transferred to the house of Hanover or Windsor when The Stuart line died out. After all, the Stuarts didn’t get to keep Buckingham Palace, why should they be allowed to keep any of the other royal possessions?