The record of the National Fruit Collection, at Brogdale in Kent, describes it1:
Said to have originated from Finale Ligure, Trentino or Calabria, Italy. First described in 1817 but thought to be considerably older. Fruits have fine, loose textured, melting, white flesh with a sweet and perfumed flavour.
Sources
Mela Carla (accession 1947 - 004), National Fruit Collection, Brogdale, Kent (Defra).
Supports: the description quoted; the use; the fruit's size, shape and colours and the flesh, from the collection's characterisation; the picking time at Brogdale (early october); the other names.