I have been looking at Jeanne Marchig's testimony to the New York court on 17 Jan 2012.
She testified that "I had inherited the drawing from my late husband, Giannino Marchig (1897-1983), who was an art restorer and artist, and an expert in Italian Renaissance art. At that time the Drawing was in an antique ornate Florentine wooden frame, which it had been before I married him in 1955".
François Borne of Christie's, rejecting the idea that it came from the Renaissance, as her husband and she firmly believed (though no mention by anyone of Leonardo), said that "your superb German drawing in the taste of the Italian Renaissance fascinates me. I think it is an object of great taste". He advised her "to change the frame in order to make it seem an amateur object of the 19th century not an Italian pastiche". The old frame (now disappeared), which looked like an Italianate mock-up from the 19th, was removed and replaced against Jeanne's wishes, and she did not approve of its cataloguing as German, but she felt she "no choice but to accede".
The date of 1955 rules out Greenhalgh (as do many other things), and works strongly against any other forgery theory, since the scientific examinations reveal features of which no forger could have been aware at that time. This applies to the scurrilous and unsupported identification of Marchig as the forger and to any other pre. 1955 forgery.
All that is left is for opponents to divert the argument into claiming that Jeanne Marchig lied profusely. She seemed to me to be a person of great credibility. I wish she were still with us to confirm the truth, which is evident to anyone who looks at the evidence with an open mind.