Firming up your theory of a runaway couple, there is no death entry showing in Scotland for a Margaret Morrow/Little...nor can I see any children showing on IGI for William Little and Margaret Morrow?
I assume that this is the submitted entry you mean on IGI (I can also see the many children that show for them in Australia):
MARGARET MORROW Birth: 1849/Death: 10 NOV 1918
Parents: JOHN MORROW MARY ANN TROTTER
Marriages: Spouse: JOHN LAVERY Marriage: About 1868 Glasgow, Lanark, Scotland
The parent names showing above certainly tie up with what looks like Margaret's entry in 1861 at home with family prior to her marriage later that year in Kilbarchan to William Little:
John Morrow 52
Marianne Morrow 58
Richard Morrow 16
Robert Morrow 14
Margaret Morrow 11, b. Glasgow
James Morrow 8
Address: Balmorrol Cottage, Kilbarchan
I think your hunch may be spot on! Hopefully, if you are lucky with Ann Warnock's poor relief records, at least some of it may be confirmed.
Regards.
Monica
ADDED: I'm not sure where you are located but it might be worthwhile following up on death certs in Australia for John Lavery and Margaret Morrow. Although, going the amount of submitted entries including marriages for their children in Australia and a death date for Margaret Morrow, it is looking likely that you have the right couple. It would help you to see some confirmation of John's parents' names as well.
....I've just seen, you're in Lancashire so maybe not so practical
