Ah, Camilla was ‘ol’ Charlie's gal long before she got married…. And apparently continued to be even after ‘ol’ Charlie ‘married’ Diana…. Now that does paint a picture that Diana had a better bloodline for production of heirs, than did Camilla..
I read someplace long time ago that Diana had as much ‘royal’ blood as ‘ol’ Charlie.. I do not remember where or when.. The ‘firm’ does what it needs to appear above the rest.