It would be Charles' decsion on most valuable items as the Monarch leaves most possessions to the next monarch, so there are no death duties etc. payable. As the capital transferance tax, etc. could come into play, "life loans" are the more normal method. As to the late Queen's personal jewellery, it would depend on what she considered hers and hers alone, versus what she considered her as queen (outside of the Crown Jewels themselves). I would imagine that some items were given directly to certain recipients, either during her lifetime or in her own will. For example, she might leave the Grima brooch gifted to her to an individual but would not do the same for the Girls of Great Britain tiara, despite both being hers.