Clotted cream? I don't think of crème fraîche as being clotted cream.
Here are the online Oxford's definitions: crème fraiche
Pronunciation: /krɛm ˈfrɛʃ/
a type of thick cream made from double cream with the addition of buttermilk, sour cream, or yogurt. http://www.oxforddictionaries.com/definition/...
(mass noun) chiefly British
thick cream obtained by heating milk slowly and then allowing it to cool while the cream content rises to the top in coagulated lumps:
(as modifier): they serve clotted cream teashttp://www.oxforddictionaries.com/definition/...
I wouldn't want crème fraiche on my scones or clotted cream on my Flammkuchen. ;-)
I take your point, though, that you could probably make crème fraiche from clotted cream by adding the sour ingredients.