Do you think the use of the crown was limited to the Khedive's family? Or could it be EC for Evelyn Baring, 1st Earl of Cromer, who was the British controller-general in Egypt?
Royal cypher was in Arabic,but there is Ismail Pasha monogram in Latin letters on glass,porcelain and pocket watches. There were many members of the dynasty and they all had the right to use the crown,so,difficult to tell. Regards