Thanks for that. If she is a wife and from Halifax, it is almost certainly the wrong person. The document I found on Ancestry said she was a servant, it was a different document, but it does seem to be the same people as on the Ancestry document where she is listed as a servant, she is also listed between Thomas Darby, labourer and Mary Mines, servant. Also her age, 30, is in the column for single people not the column for married people. So the two documents show different information, one that she was married and the other that she was single and a servant. But as far as I know, my great aunt was last living with her parents in Hollingworth, near Manchester, not Halifax, and that was on the 1891 census, so she might have been living as a servant in Halifax immediately before travelling...
Greenwood was a very common name in West Yorkshire and nearby, so lots of false leads. I thought the combination of her age, birth year, disappearance from English records, and likelihood that she was a servant, might mean I had the right person.