I want to say it is one of the original Maybachs. But that could, and probably is, a wildly inacurate guess.
She is an Allard. Yes, she is British ... however, she may well carry a US engine. Anything from a Ford, Chrysler, or Cadillac engine was "original". In a way, this beauty was the hybrid grand-daddy of the Cobra. There is a convertible for sale at Hyman Classic Cars .... check out their website.
Yes , it is a street version of an Allard, but "beauty" is in the eye of the beholder, try the Allard J2X. Hov