I grew up in Spring Valley myself Liz. Due to my grandmother's influence I was brought up Catholic and knew Father Hannon who oversaw the Parish of The Sacred Heart Church in Pulrose,(As you quite rightly said, sadly it's demolished now). St. Mary's was the main church in Douglas, it's still there. I think the Nun around Pulrose might have been the one that was attached to St. Mary's school located near St. Ninians! She was a but strict and all us convent girls feared her much more than our own nuns! She didn't live at the convent, perhaps she was from another order!