From a London private collection

It appears that this broken and dirt-coated Greek terracotta protome once formed part of the (extensive) London private "collection" of an anonymous individual or individuals. One suspects that at the time that the photograph was taken that the piece, and its companion, was fresh from the ground, perhaps removed from the site of a Greek colony in southern Italy or Sicily.

It has to be remembered that "collection" can sometimes be a euphemism for "dealer's stock" (see here for a parallel example).

Imagine how the collecting history of this protome would be presented if it appeared on, say, the London market today.