The record of the National Fruit Collection, at Brogdale in Kent, describes it1:
Originated in about 1770 in Champagne, France. Fruits have firm, crisp, rather dry, greenish white flesh with a slightly sweet, slightly subacid flavour.
Chusenrainer× Sauergrauschapfel; Switzerland, about 1852
Sources
Reinette de Champagne (accession 1948 - 667), 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 (late october); the other names.