OUR recent story about the identity crisis afflicting glam entrepreneur Nancy Miller Jong has taken on a new sense of urgency. For we hear that Nancy - who used to be Jong before she became Miller and then reverted to Jong because she was no longer Miller before deciding to carry both surnames (you get the general drift) - was staying recently at the Dorchester, which is her London base, when the most unholy mix-up occurred. A businessman friend living in Paris had invited Nancy over for a chic party and even sent his private jet to London to fetch her. Unfortunately, he had given instructions to his people in London to contact ''Mrs Miller'' at the Dorchester and arrange for her to be taken to the airport just outside London to board his plane. Nancy, alas, was checked in the hotel as ''Ms Jong'' and they had no idea who ''Mrs Miller'' was. To cut a long sorry story short, the flight connection was not made and poor Nancy was all dressed up with nowhere to go. The Dorchester, which was profusely apologetic over the mix-up, tried to make amends by sending up a huge bouquet of flowers to her suite. At least there is no room for error when she checks in the next time around as Nancy Miller Jong.