many thanks for your reply,
Unfortunately I do not have a year of birth for her, however, she married her husband just before the First World War, straight out of university we believe. Her husband Aladar Elfer was her university professor at the University of Kolosvar before the war. This would put her at about 25 at the outbreak of the first world war in 1914, making her date of birth probably sometime in the 1880s.
She was one of three sisters, one of whom was called Ávey Dávid.
She married Aladar Elfer a year or so before the war, however we do not know where. It would either be in Covasna county or in Kolosvar, where he lived.
Her son with Aladar was my Grandfather, György Elfer who was born in Kolosvar. She divorced Aladar at some time and married Zoltan Szantó who later, upon all his property being taken by the Nazis, committed suicide. Margit died in Switzerland where her son Baláint Szantó lived.
Many thanks for any help you can offer.