Questions are being raised about the British Museum's security protocols, its handling of thefts, and how long senior management was aware before action was taken. Now, Greece is renewing its calls for the return of the Parthenon Marbles.
Only the things they couldn't carry. There was a colossal head and arm of an Egyptian statue in the British museum, and a plaque saying the rest of the statue (body and legs) were still where they found it. Presumably because they were to heavy to take back.
There are some things - there are quite a few things that were either gifted by ambassadors or legitimately bought (as opposed to the dubious purchase of the Partheneon marbles) and also British artefacts.