Secondary School pupils, about 1953

We are not certain of the year when this photograph was taken. Can you help?

The people in this picture are:
Arthur MacEachen, Duncan MacLellan (Bunny, Mallaig, Ian Boyd, James MacLellan (Jimmy Traigh), James O'Donnell, Margaret Stevenson, Valerie MacLellan, Mary Miller (Bracara), Isobel MacEachen (Tougal), Helena Cook, Jim Martin, Donald Shannon, Helen O'Donaghue, Ruth Downie, Ann MacDonald, Mary MacDonald (Sunisletter), Mary MacDonald(Kilmory), unidentified , unidentified , Ian MacDougall, Arthur Innes, John Cadden