Okay, now I'm confused.
As I understood it, Princess Diana was merely the affectionate name given her by the public but was not at all official.
She was never referred to as Lady Diana, Princess of Wales, I thought, but rather was Lady Diana Spencer before marriage, her title from birth, and designated Diana, Princess of Wales afterward. Interestingly, Diana was actually more English than Charles as the Spencers trace their line back to the 1400s in England.
At the divorce, she was granted the right to continue using Diana, Princess of Wales but did not retain the HRH since it came to her by marriage. Divorce removed that title.
Am I correct?