This sounds like the Convent of the Holy Cross in Bolnore Road Haywards Heath. which was opened in 1887 by an order of nuns that moved down from London. It included an Orphanage of up to 60 children from infancy to 18 when they left to go into service. the orphanage closed in 1926. The convent closed in 1980 but the order still exists in Nottingshire. My Great Grandfather George Nichols moved down from London with the convent and the Nichols family worked for them for 5 generations My Great Grandmother Sarah was Matron of the Orphanage. Hope the attached photos will be of Dennis Nichols