A number of newspapers at the time stated that receiving the necklace was contingent on the then Princess Maud marrying. And this has been repeated by a number of modern commentators.
But there is nothing in the Duchess of Inverness' will about this. Under normal circumstances during that era, a person legally inherited once they turned 21 years, the then legal age. Until such time an inheritance was theoretically in the hands of the executors. I strongly suspect that the necklace was placed in the care of the then Prince of Wales and that either he or Queen Alexandra decided to release it only when their daughter married. The question is why would they do that??
Has anyone ever read a biography of Queen Maud which might shed some light on this issue? Queen Maud was well over 21 years when she married!!