Crennell is one of those names that changes with the writer.

1901 has in West Derby Liverpool:-

John H Crennell 40 Police Constable Isle of Man
Emily A. 42 wife Isle of Man
Thomas H. 17 son cabinet maker Liverpool
John H. 14 son App. cabinet maker
Alfred 11
Eleanor H. 6
Adara 3

John H. Crinnell married Emily A. Clague 1883 at Christ Church Edge Hill Liverpool .

If you look at the 1881 census on line a John Cringle age 21 policeman is in the same household as Emily Clague 22 with others.

Len Faragher