Caveat Emptor: The Warren Cup, a piece of mimetic craftsmanship around 1900?

To be honest, I thought this question had already been settled a while ago, it seems not. There is going to be a public talk on 12th March 2014 at King's College London hosted by the King's Classics Department and Institute of Classical Studies and featuring a presentation by Prof. Luca Giuliani (Humboldt-Universität zu Berlin / Wissenschaftskolleg zu Berlin), with response by Prof. Dyfri Williams (Université libre de Bruxelles):

The Warren Cup: A piece of mimetic craftsmanship around 1900?

Brilliant phrase that, "mimetic craftsmanship" (metal detectorists: that means "fake"). Here's the blurb:

The 'Warren Cup' - a small, silver drinking cup decorated in low relief with scenes of homosexual intercourse - was purchased by the British Museum for £1.8m in 1999; today, it is one of the most cherished pieces in the British Museum's Roman Galleries (and a highlight of Neil MacGregor's History of the World in 100 Objects). In this lecture, Prof. Luca Giuliani re-examines the cup's modern reception since its initial purchase by Edward Perry Warren in 1911. Rather than date the cup to the first century AD, however, Prof. Giuliani suggests that the object is in fact a modern forgery, its imagery specially designed for its first, eponymous owner. Luca Giuliani's research on the 'Warren Cup' has attracted much media attention in Germany. This will be the first time that Prof. Giuliani addresses a British audience on the subject: to enrich discussion, the British Museum has nominated Prof. Dyfri Williams (author of The Warren Cup, published by the British Museum Press in 2006) to act as respondent.

The object was once cited as a prototype of a certain series of Arretine ceramic cups much collected by Victorian British clergymen (a fine series in the Ashmolean), when it is more likely it was modelled after them.  Prof Giuliani observes that one of the sexual positions depicted is copied from an Arretine depiction of vaginal copulation, but the artist applied it anatomically incorrectly to anal copulation, thus (it is suggested) giving the forgery away. (This logic is surely only watertight if one assumes that an ancient artist depicting a homoerotic scene had actually practised anal sex him/herself.)

M.T. Marabini Moevs 2008, "Per una storia del gusto: riconsiderazioni sul Calice Warren," in Bollettino d'Arte, (Ministero per i Beni e le Attività Culturali) 146, Ottobre -Dicembre 2008, pp. 1-16
Luca Giuliani 2013: 'Ein Kelch für Mr. Warren', Zeitschrift für Ideengeschichte 7 (3), 77-92.
Luca Giuliani 2013: 'Falscher Sex', Die Zeit 15. August 2013, p. 54; 

Anon, "Auf dem Weg zu Vulva oder After?" Berliner Zeitschrift,  Dienstag 11. März 2014. 

Vignette: naughty relief on a cup.

UPDATE 13.03.14
I forgot to mention this on the Chasing Aphrodite blog, a few details on Mr Warren: 'The Dark Side of Aphrodite: The Getty’s New Aphrodite Show Features Collection of Famous Pederast', Chasing Aphrodite March 28, 2012.