Jane, I've emailed you some information as promised on my line descending from John Killey (1810).
It occurred to while looking at my records that I don't have a copy of the marriage record for John Killey (1810) and Jane Hutchin. I think I was saving that for a future search or board post. Perhaps John's marriage record might give some more information than that provided by the other siblings - William, Mary, Eleanor, etc. Is anyone on the board able to access that marriage record? They married on 11 August 1832 in Jurby (info. on IGI).
Jane, your theory about Ruth possibly moving to England seems plausible and worth checking.
I am sure the more information we get on each sibling the more chance we have of tracing back beyond their parents, John Killey and Mary Callow.
A big thanks from me too to everyone who has contributed to this Killey post to date.