Sorry this is a bit late, 5 years! Three of us are investigating the Strappini family.
Constance was I think the step-sister of Gertrude. She was born about 1883 to Moses and Mary Ann E Edwards and adopted by Michaael and Elizabeth Strappini. She is in the 1901 census record with Elizabeth after Michael's death in Station Road Kirk Michael.
Any information you could give us would help. Especially anything to do with Michael.
We believe she married James Milne Jarvie and they were both alive in 1963 when thye had a golden wedding notice in The Times.