This one came out of the blue from the Art Newspaper:

The Art Newspaper can reveal that the Turkish government has made a claim for a decorated stele in the British Museum (BM). This happened after a Turkish diplomat in Japan spotted the antiquity on loan to an exhibition on “Alexander the Great: East-West Cultural Contacts from Greece to Japan”, which was shown in Tokyo in 2003. It was not until last September that a letter was sent by the Turkish embassy in London. Although there is much talk of restitution claims against the BM, official requests are comparatively rare.

The basalt stele, dating from the first century BC, depicts a relief of Herakles greeting the sun-god, with a Greek inscription on the reverse. It was later reused as an oil-press, and hence the hole in the middle. The stele was excavated by Leonard Woolley in a field at Samsat, near the Turkish-Syrian border, probably in 1917-20. It was purchased by the BM from the Carchemish Exploration Fund in 1927.

BM director Neil MacGregor discussed the case with Turkish ambassador Akin Alptuna last autumn. Mr MacGregor is surprised that the claim had been made after nearly 80 years. He also believes that Woolley, a distinguished archaeologist operating with full Turkish authority, would almost certainly have the proper consent to excavate and export. No documentation had been produced to suggest the stele had been excavated or exported illegally. Nothing further has been heard from the Turkish embassy.

Because of the refurbishment of the BM’s Ancient Near East Galleries, the stele went into store on its return from Japan. On 12 April it went on display in room two. It will be moved to the refurbished galleries early next year.

A photo of the stele accompanies the original article; I'm pretty sure I've seen this in some textbook on eastern influences in Greek art ...