I have looked on the 1881 Census and found no Cretneys in Yorkshire. Manx people seemed to move to England regularly in the 1870's but may have taken longer to cross the Pennines! My friend Shiela's family in 1881 as follows:
38 Guildford St. Everton, Lancs. John Maddrell, head, water turncock, married, age 50; Margaret, wife, age 32; William Cretney, nephew, police constable, age 32; Jane Cretney, niece/wife of William, age 24; all born on Isle of Man, plus Margaret Cretney, daughter, age 3; Adelaide M. Cretney, daughter, age 1, both born Liverpool.
51 Tennyson Street, Toxteth Park, Liverpool: Robert H. Cretney, head, age 47, inspector of police born Isle of Man; Eliza Cretney, wife, age 44, born Flint, Wales, James W. Cowley (Cretney) stepson age 15; Isabella Cretney daughter, age 13; Frederick W. Cowley (Cretney) stepson age 13; Robert H. Cowley (Cretney) stepson age 10; all children born Liverpool, but alll must be children of previous marriages; Margaret Bowers mother-in-law, widow, 74, born Flint.
Good luck with the quest.