I don’t quite know what to make of this article. On the one hand he’s saying that the Parthenon Marbles could return to Greece, which is great. On the other hand though, he is saying that they must not become pawns of political exploitation & that the issue over where they belong must not become an obsession. Its hard to see how these can be separated out though – its almost saying that they would only be returned if Greece wasn’t really interested in them.
He then talks about how they would not be displayed on the monument – but this is not something that anyone has sensibly proposed for a long time now. The New Acropolis Museum was designed & constructed especially for this purpose & the way in which it relates to the original building has already been discussed many times on this site .
Greek Reporter 
Great Britain Challenges Greece on Elgin Marbles
by Iro-Anna Mamakouka – Feb 24, 2014
The director of London’s National Gallery, Nicholas Penny, is challenging Greece once more on the issue of the Parthenon’s Marbles, suggesting that Greece and Britain share them.
According to him, the British Museum has recognized to some extent, the profound importance that the Marbles have for Greece and that lending the Marbles to the Greek state is under discussion as long as they do not become pawns of political exploitation.
He also suggested that the British Museum would be open to discussion over sharing the Elgin Marbles provided that the issue of where they really belong does not become an obsession.
Moreover, Mr. Penny claimed that if the Marbles were to return to Greece, they would not be placed on the monument due to Athens’ air pollution. Both the monument and the marbles are not in very good condition; thus, the visitors could not see them as they were in their original position. According to Mr. Penny, this is a sentimental myth, the idea that someone can turn the clock backwards.