'Lord Elgin and the Marbles' by William St. Clair

'The Elgin Affair, The Abduction of Antiquity's Greatest Treasures and the passions it Aroused' by Theodore Vrettos.

The Elgin Marbles, Should they be Returned to Greece? by Christopher Hitchens.

These are all excellent books, the latter two certainly easily accessible, the first out of print I think. 'The Elgin Affair' was most recently published (1997) It reads like a fascinating adventure and is historically meticulous in its portrayal of greed, deceit, thievery and cultural arrogance. If it even remotely involves Byron or Keats, name the book, I've got it ;-)