It might be of interest here to say that after Prince Richard dies, the Dukedom of Gloucester will cease to be Royal. After two generations they lose their Royal status.
Richard's father Henry was a son of a monarch (George V) and Richard a grandson and first cousin of a monarch. After this the relationship of the Duke becomes too distant from the Crown.
The same will apply to Kent when Prince Edward, the current Duke of Kent, dies.
This is why Edinburgh was changed to a life peerage - to prevent the Dukedom going out of the immediate family.