Eros and Robin Symes

Christie's (London) are due to auction a Roman statue of Eros unstringing a bow on 4 December 2019 (lot 483). The piece, 'The property of a gentleman', is provided with the following history:

Roger Peyrefitte (1907-2000) collection, Paris, said to have been acquired from Nicolas Landau in the late 1960s. French private collection, purchased from the above in 1986.

Yet Professor Christos Tsirogiannis has identified images from the Schinoussa archive suggesting that the Eros had passed through the hands of Robin Symes at some point (Dalya Alberge, "Christie's urged to pull sale of Roman statue 'linked to illicit dealers'", The Guardian 24 November 2019).

When in the sequence did Symes handle the Eros? Why does this information not appear in the stated history? Is the stated history supported by authenticated documentation? Did Christie's check the piece with the relevant authorities in Greece or Italy?