Leslie Howard's death mistery: the man in the photo

Ronald Howard, actor and Leslie Howard's son, wrote in 1981 a book about his father's life and death, In Search of My Father. There he publishes a photograph of daddy dining in Hotel Aviz with Alfred Chenalls and a man he declares to be Calouste Gulbenkian. But, after a book I wrote, I came to conclude that he couldn't be the oil mogul. Howard’ case still remains a mystery after IBIS aircraft KLM/BOAC was in 1st June 1943 sunk by a German Junkers flotilla in Biscay Bay, despite a gentleman’s agreement between the Allies and the Axis in order to spare the Lisbon air line from any attack by the Luftwaffe.
Who is the man having dinner with the famous actor, days before his tragic fate?